Frankie Dettori has returned to the spotlight in a very different way, joining the Celebrity Big Brother house.

The flamboyant jockey was the first to enter the stage at studios in Elstree, Hertfordshire.

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 Dettori could be involved as he is currently serving a six-month riding ban after testing positive for a prohibited substance at Longchamp in September.

"I've been in the press recently for the wrong reasons," Dettori said.

"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."

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.

Bookmakers seem convinced Dettori has a winning chance, with Coral spokesman David Stevens saying punters would back him.

"Frankie Dettori has cost the bookies millions over the years, including STG40 million ($A62.32 million) in one day alone when he rode all seven winners at Ascot in 1996," he said.

"He was well-backed to appear in a reality TV show this year, forcing us to suspend betting before Christmas. He is sure to have a huge following among punters."