Megan Fox cheated on husband - reports

Los Angeles - Shia LaBeouf reportedly had a fling with Megan Fox on the set of Transformers - while she was engaged to current husband Brian Austin Green.

The co-stars, both 25, enjoyed a brief fling while filming the action movie in 2006, although Shia claims to have no knowledge of whether Megan was still with her then-fiancé at the time.

He said: "Look, you're on the set for six months, with someone who's rooting to be attracted to you, and you're rooting to be attracted to them. I never understood the separation of work and life in that situation. But the time I spent with Megan was our own thing, and I think you can see the chemistry on-screen."

Asked if Megan and Brian - who got engaged in 2006 and broke up in 2009 before reuniting and marrying in 2010 - were together at the time of their fling, Shia told Details magazine: "I don't know, man. I don't know. I don't know. I don't know. It was what it was."

After his brief relationship with Megan, Shia dated Carey Mulligan and although the couple are no longer together, he admits he still loves her.