Megan Fox was in tears over Shia's hook-up confession

Shia LaBeouf apparently couldn’t help himself when asked by Details if he hooked up with former Transformers co-star Megan Fox.

"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 onscreen," he said.

And when asked if she was with her now-husband, Brian Austin Green, when they hooked up, he may have realized the seriousness of his confession as he stumbled over his words, saying, "I don’t know, man," 12 times.

As it turns out, Fox and Green were on a break when she hooked up with Shia (they married June 2010) but his confession has reportedly caused some conflict in their marriage.

"Megan's been in tears, and is apologizing to Brian -- even though technically she didn't do anything wrong since they were on a break... They are so angry at Shia," a source tells OK Magazine.

No word if Shia has apologized directly to Fox, however, he told Access Hollywood he is learning to keep his mouth shut. "I just turned 25," Shia said. "And I’m learning how to edit myself and say 'no comment' now."