Dettori in Big Brother house
(Healy Racing Photos)
The multiple Classsic-winning jockey, 42, was the first to enter the stage at studios in Elstree, Hertfordshire, and was immediately set a challenge, being paired with the X Factor's Rylan Clark and asked to make a series of decisions that would affect fellow housemates, involving splitting contestants into either the luxurious house or a grim basement area, lacking hot water and readily available food among other things.
As always, the line-up for the latest series of the show was a closely-guarded secret, but it had been rumoured for some time that the Italian could be involved as he is currently serving a six-month riding ban after testing positive for a banned substance at Longchamp back in September.
Speaking during his introduction, Dettori said: "I've been in the press recently for the wrong reasons.
"I was going through a very bad time in my career, one minute of madness and I slipped up. All the publicity you read about in the newspapers, I'm deeply ashamed about it but move on and look forward to the future.
"I don't know if I'll be a good housemate or not, I'm quite selfish, I blow hot and cold. I do get on with people quite well, I don't know if generally people get on with me that's the problem!"
Asked by host Brian Dowling about recent events, Dettori said: "That was 2012, this is 2013, let's have a new start."
Dettori is no stranger to television fame, having been a captain on the BBC's long-running A Question Of Sport from 2002 to 2004.
The contestants will spend the next few days holed up in the custom-built property in full glare of TV cameras with a winner emerging later this month if they can prove popular enough with viewers and their own housemates. The series is expected to last three weeks, with the first eviction due on Wednesday.
The series of Celebrity Big Brother is the fourth to be screened by Channel 5 in the space of 18 months, after resurrecting the show which had been dropped by Channel 4.
The Willie Mullins-trained Briar Hill pulled away stylishly in the closing stages to make a winning 'track debut' in the concluding bumper at Thurles.