Cameron Diaz has agreed to marry an unknown comic book fan.

The 'What Happens in Vegas' actress was given the unexpected proposal when answering questions from fans at the Comic-Con 2009 convention in San Diego, California.

The unidentified man shouted out to the Hollywood actress: "Will you marry me?"

She answered: "Yes! Where are you? Why not?"

However, Cameron did have one stipulation for her potential fiance - that they tie the knot in the US gambling capital Las Vegas.

She added: "Can we get married in Vegas? I always wanted to get married in Vegas."

The beautiful star also told how, despite being at the convention to promote her new movie, psychological horror 'The Box', she can't watch scary movies.

Cameron, 36, said: "You know what terrifies me? Trailers to horror movies!

"I kind of want to look, but I'm always afraid that I'm going to look too long and see the one image that I'm not going to be able to get out of my head for at least a week every night before I'm going to bed."

'The Box', directed by 'Donnie Darko' creator Richard Kelly and also starring James Marsden, is set for release in December.