Shia LaBeouf's passenger at the time of his car crash has been identified as Australian actress and girlfriend of Adrian Grenier, Isabel Lucas.

Lucas – LaBeouf's co-star in the Transformers sequel – was treated in hospital for minor injuries after the actor's truck collided with another car in West Hollywood on Sunday.

"She was in the car....They're friends," a movie source tells the New York Daily News.

Entourage star Grenier – who has dated Lucas for 'months' – was apparently "testy" when asked by reporters about his girlfriend's involvement in the smash-up.

LaBeouf was taken to hospital following the accident where he was treated for injuries to his head, left hand and knee.

The star is expected to be absent from the Transformers set for a while as he recovers from surgery on his damaged hand.

He has since been charged with misdemeanor DUI.