The Transformers star split from Mia last summer (15) after he was caught on camera verbally chastising the actress on a street in Tubingen, prompting a group of male strangers to step in and break up the fight.

Shia was subsequently linked to another actress, Sasha Lane, after walking hand-in-hand with her in California in August (15), but it appears he has since rekindled his romance with his ex.

The former couple was photographed openly kissing in the middle of a crosswalk after a lunch date in Los Angeles on Wednesday (06Jan16), when the usually-private Shia made no effort to hide his affection for his Nymphomaniac: Vol. II co-star.

The 29-year-old first began dating the British actress in 2012.

Their on/off relationship hit headlines in July (15) after Shia was filmed shouting at a silent Mia during a fall out in Germany.

"I don't wanna touch you," he could be heard saying in footage obtained by U.S. news show Entertainment Tonight. "I don't wanna be aggressive. This is the kind of s**t that makes a person abusive."

It is not known what the pair had been arguing over, but the fight was volatile enough for some locals to intervene and offer Shia a ride to the airport.

In the car, he continued to discuss the domestic dispute with Mia.

"I don't want to touch a woman," he told the men. I don't want to hit a woman. But I'm being pushed. If I'd have stayed there, I would have killed her."