Celebrity Big Brother 1, also referred to as Celebrity Big Brother 2001, was the first series of the British reality television show Celebrity Big Brother. The show is based on an originally Dutch TV series of the same name created by producer John de Mol Jr. in 1997. In honour of Comic Relief, six celebrities entered the Big Brother house.

The series premiered on 9 March 2001, and lasted for a total of eight days. It concluded on 16 March 2001 when comedian Jack Dee was crowned the winner. The series revolved around a group of celebrities living in a custom-built house with no contact with the outside world. Each week, the housemates are required to nominate two people for eviction. The two or more people with the most votes were nominated to leave the House. The viewers then decided which of the nominees should leave, with the selected person leaving during a live show. This process continued until only three housemates remained, at which time the public voted for which of them should win the series. Unlike the original show, Celebrity Big Brother saw the housemates competing for charity.

On 17 March 2023, a special twenty-second anniversary show aired as part of the 2023 Comic Relief event. The show titled When Comic Relief Did Big Brother was broadcast at 10pm on BBC Two. It featured interviews with five of the six housemates (Chris Eubank did not participate) with a look back on the series and their time in the house. Marcus Bentley narrated the episode.

The series premiered on 9 March 2001, on Channel 4. The contestants were recorded 24 hours a day with cameras fixed around the house, and had to wear portable microphones. Due to the tie-in with Comic Relief, the first series was partly broadcast on BBC One in the week leading up to the telethon. Channel 4 broadcast a daily 30-minute highlights show, and from the second day on there was a live eviction show hosted by Davina McCall, where the evicted housemate was interviewed. In the nightly highlight episodes, viewers are shown various highlights of a specific day in the house. BBC One's coverage consisted of a behind-the-scenes launch show hosted by McCall and 10-minute-long updates each day. Due to the length of the series, the psychologists featured in the main series did not return for Celebrity Big Brother 1, but did continue to appear in the main series. The series ended on 16 March (Red Nose Day) and the finale was broadcast live on both Channel 4 and BBC One as part of the evening's Comic Relief telethon. In total, the series lasted for a total of 8 days. Initially, Celebrity Big Brother was meant to be a one-time series, but due to the success it was later brought back as an annual event, airing while the main series was completed. Celebrity Big Brother 1 was the first season in the UK edition of Big Brother to feature a live premiere, something that would be used from Big Brother 3 onward.

The six celebrities in the game are competing for charity, rather than a grand prize for themselves. While in the house, the housemates attempted to complete various tasks assigned by Big Brother in exchange for a grocery budget, which they used to buy food and luxuries; this included buying things such as alcohol and cigarettes. Celebrity Big Brother 1, much like the main series, did not feature luxury competitions or prizes throughout the season.

For the first season, Celebrity Big Brother used the house that was used in Big Brother 1, which was located in Bow, London near the 3 Mills Studios. The House remained relatively unchanged from its appearance in the debut season. A living room was featured in the house, with blue walls lining it and the kitchen, which featured a stove and sink, along with the fridge. The house featured two nearly identical bedrooms, one for the men and one for the women. Each room featured five beds, with matching sheets and furniture. There was a shower room and toilet in the house as well. Housemates could communicate with producers in the room known was the "Diary Room". The Diary Room for the first season featured a simple design, being a small chair with a white background. Future seasons of the series would feature more elaborate Diary Rooms. The Diary Room was where nominations took place, and where housemates could reveal their thoughts. As seen in the third week, housemates could be seen by a medical professional in the Diary Room if necessary. The outside of the house featured a chicken coop with various chickens inside, from which the housemates collect eggs. Unlike other editions of the show, Big Brother 1 did not feature a swimming pool or hot tub for the housemates to use. There was also a garden in the backyard, which featured a vegetable patch which the housemates could use. Various two way mirrors are in the house, with a camera crew behind them. There are also various cameras and microphones throughout the house, providing the housemates with no privacy.

Big Brother is a game show in which a group of contestants, called housemates, live in isolation from the outside world in a custom built "house", which includes everyday facilities such as a fully equipped kitchen, garden, two bedrooms, and a bathroom. The house is also a television studio with cameras and microphones in most of the rooms to record the activities of the housemates. The only place where housemates can escape the company of the other contestants is the Diary Room, where they are encouraged to voice their true feelings. Not all Diary Room footage is broadcast due to the privacy of the contestants. Each week all housemates nominate two of their fellow contestants for potential eviction. Failure to do so may result in a punishment, such as a reduction in the prize fund. The two, or more, housemates with the highest number of nominations face a public vote conducted by phone, with the contestant receiving the most votes being evicted from the house. The last contestant remaining in the house is declared the winner and will earn money for a charity. Big Brother host Davina McCall returned for Celebrity Big Brother to host the live premiere and eviction episodes. The eviction episodes remain largely unchanged from that of the main series.

Over the duration of the series, the Housemates are given a series of tasks by Big Brother which test them in many ways. They are also put to the test by their own ideals, prejudices and opinions against other people from different walks of life; something that has survived from the original "social experiment" of Big Brother 1. They live in the communal House and share cooking and cleaning chores among themselves, which usually provides plenty of tension. Housemates are forbidden to sleep during daylight hours (unless unwell) - Big Brother plays the wake-up call persistently in the morning if housemates do not wake up and will play an alarm clock noise into the house if a housemate falls asleep during the day. Housemates must also live by the fundamental rules of Big Brother; if the rules are broken it can result in formal warnings, various punishments or even a housemate's removal from the House. They must wash their own clothes by hand, and they have to make their own bread from scratch. Each week Big Brother sets the Housemates a task in order to determine the shopping budget for the following week. They must work together to win the tasks in order to win a luxury shopping budget which changed based on the number of people remaining in the house. If all food runs out in the House, Big Brother provides emergency rations of chickpeas and rice. Housemates are responsible for their own shopping and decide which items the budget will allow them to have. Only a small percentage of the overall budget can be spent on alcohol.

Celebrity	Age on entry	Notability	Day entered	Day exited	Result
Jack Dee	39	Comedian	1	8	Winner
Claire Sweeney	29	Brookside actress	1	8	Runner-up
Keith Duffy	26	Boyzone member	1	8	3rd Place
Anthea Turner	40	Former Blue Peter presenter	1	6	Evicted
Vanessa Feltz	39	TV presenter,broadcaster & journalist	1	4	Evicted
Chris Eubank	34	Professional boxer	1	2	Evicted

Day 1
	Entrances	Anthea, Chris, Claire, Jack, Keith and Vanessa entered the house.
	Nominations	Housemates nominated for the first time. Anthea and Chris received the most votes and faced the public vote.
Day 2
	Tasks	For their first task, the housemates had to customize a pair of pants for another fellow housemate. They then had to perform a fashion show with their creations. They passed the task and Big Brother played Westlife's Comic Relief song into the house.
	Exits	Chris was the first housemate evicted from the house after receiving 66% of the public vote to evict.
	Nominations	After Chris' eviction, the housemates nominated for a second time. Jack and Vanessa received the most votes and faced the public vote.
Day 3
	Tasks	The housemates were given their second task, in which each housemate had to memorize 10 facts about each other. They were then asked three questions at random later in the day. They passed and won a luxury shopping budget.
Day 4
	Tasks	The housemates were given their third task, in which they had to make a topiary model. They passed the task and won a film to watch
	Exits	Vanessa was the second housemate evicted from the house after receiving 71% of the public vote to evict.
	Nominations	After Vanessa's eviction, the housemates nominated for a second time. Anthea, Jack and Keith received the most votes and faced the public vote.
Day 5
	Tasks	The housemates were given their fourth task, in which they had to write an original song about their time in the house. They passed and won a takeaway dinner.
Day 6
	Tasks	The housemates were given their fifth task, in which they had to take part in an assault course. They passed and won a luxury shopping budget.
	Exits	Anthea was the third housemate evicted from the house after receiving 52% of the public vote to evict.
Day 7
	Tasks	Housemates were given their sixth task, in which they all had to take care of baby simulators called "Juanita" to test their parenting skills. They passed and won a Wild West themed party.
Day 8
	Tasks	Housemates were given their seventh and final task, in which they had to paint their favorite view of the house.
	Exits	Keith left the house in third place. Jack was announced as the winner, leaving Claire as the runner-up.

	Day 1	Day 2	Day 4	Day 8 Final		Nominations received
Jack	Anthea, Chris	Vanessa, Anthea	Anthea, Keith	Winner (Day 8)		8
Claire	Anthea, Chris	Vanessa, Jack	Jack, Keith	Runner-up (Day 8)		2
Keith	Chris, Jack	Jack, Vanessa	Anthea, Claire	Third place (Day 8)		6
Anthea	Chris, Keith	Keith, Jack	Jack, Keith	Evicted (Day 6)		6
Vanessa	Chris, Jack	Keith, Jack	Evicted (Day 4)			3
Chris	Claire, Anthea	Evicted (Day 2)				5
Note	none			1
Against public vote	Anthea, Chris	Jack, Vanessa	Anthea, Jack, Keith	Claire, Jack, Keith
Evicted	Chris 66% to evict	Vanessa 71% to evict	Anthea 52% to evict	Keith 16% (out of 3)	Claire 41% (out of 2)
				Jack 59% to win

• ^1 : The public were voting for the Housemate they wanted to win rather than to evict.

These viewing figures are taken from BARB.

Day	Viewers (millions)
Fri	4.58
Sat	4.01
Sun	4.41
Mon	4.93
Tue	6.11
Wed	6.60
Thu	5.69
Series average	5.2m

• Celebrity Big Brother at IMDb

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