Brook has said she was a "huge fan" of the talent show
Model and actress Kelly Brook has been axed as a judge on Britain's Got Talent after just six days in the job.
The 29-year-old was unveiled as a new judge on the ITV show only last Tuesday alongside Simon Cowell, Piers Morgan and Amanda Holden.
She had been attending auditions in Manchester but after reviewing the tapes, the show's producers decided the new panel was too "complicated".
Cowell said the format did not "support another judge".
In a statement, Cowell said: "I have genuinely enjoyed working with Kelly, she is absolutely lovely and a complete professional.
"But it's become clear the format doesn't support another judge and we will never add a fourth judge to the panel."
When he recruited her, Cowell said she had "absolutely no idea what she's let herself in for".
A spokesman for production company TalkbackThames added: "The format of the show is cleaner and less complicated with just three judges, which was not fully appreciated ahead of filming.
"Although Kelly brings a huge amount of warmth to the show and we've loved having her on board, the complications it adds to the filming process and format of the show means that unfortunately, and with huge regret, we have agreed with ITV not to proceed with a fourth judge."
Brook - who is dating England rugby union international Danny Cipriani - has been left "stunned" by the decision, according to the Daily Mirror.
After being signed up with a reported £200,000 contract, she said she had been a "huge fan" of the show since its first series.
Brook, who trained at London's Italia Conti stage school, said: "With my dance background, I cannot wait to see the dancers."
Her first major TV job came in 1999 when she succeeded Denise Van Outen as co-presenter of The Big Breakfast, alongside Johnny Vaughan, at the age of 19.
But her performances on the show were heavily criticised in the press and she left the show after just six months.
She slowly rebuilt her on-screen career, presenting Celebrity Love Island, appearing in several TV shows and films in the US - including Superman spin-off Smallville - and competing in Strictly Come Dancing. Last year, she made her West End stage debut in the comic play Fat Pig.
Her recruitment on Britain's Got Talent followed the successful addition of Cheryl Cole as an extra judge in the last series of Cowell's other big UK show, The X Factor.
The winner of Britain's Got Talent pockets £100,000 and the chance to perform for the Queen at this year's Royal Variety Performance.
The third series of the show will be broadcast this spring.