The former Strike It Rich presenter has signed up to join tour guide Brendan Sheerin on the "holiday of a lifetime".
Following the huge success of the first celebrity run last year, which regularly pulled in over 2 million viewers, Channel 4 has commissioned two further series. The broadcaster has also given the green light to series seven and series eight of the non-celebrity format.
Channel 4's head of daytime Helen Warner said: "I'm so proud of the success of the Coach Trip format and I can't wait for the return of Brendan and his band of celebrity and non-celebrity Coach Trippers."
The two celebrity editions of the show will air this summer, followed by a normal series in the autumn. Coach Trip series eight will follow in 2012.
According to the Daily Star, Jodie Marsh and Big Brother 3 contestant Spencer Smith were also signed up for the second celebrity run, but Marsh has pulled out because she refuses to spend time with Barrymore. The pair famously clashed when they were in the Celebrity Big Brother house together in 2006.