Adrian Grenier isabeladrianover.jpgArchive photo

Entourage star Adrian Grenier has broken up with his girlfriend, Isabel Lucas, Us reports...

You might remember Isabel as Shia LaBeouf's passenger in that car crash back in late July. Is there a connection between that and this split? You betcha!

A source tells Us: "All that stuff that happened with Shia definitely didn't help things. When Adrian saw Isabel with Shia, he knew it was time to move on and made the decision to end things."

Still, the 32-year-old actor thinks Isabel is a "really sweet girl," according to the source.

Hmm, does this mean she's dating Shia now?