She admits she wasn't "over Justin" when she appeared alongside Colin at the opening of his 2003 movie, "The Recruit." She says she was vulnerable after the split with Justin, but tried to convince herself "it was not a big deal" and she was "just having fun" with Colin.
At the premiere, Colin told the media he was "not dating" Britney, but referred to her as "a sweet, sweet girl."
That same year, Britney told "W Magazine" she kissed Colin and thought he was the "cutest, hottest thing in the world," but their relationship was "nothing serious."
In her memoir, Britney doesn't get into what led to the end of her sexual liaison with Colin, but she offers this instead ... "For a brief moment in time, I did think there could be something there. The disappointments in my romantic life were just one part of how isolated I became. I felt so awkward all the time."
Several excerpts from Britney's book have already leaked to the media. This week, TMZ broke the story about her tell-all bombshell ... Britney and Justin made the gut-wrenching decision to abort their unborn child while they were dating in the early 2000s.