The stars, who began dating in 2007, were spotted enjoying dinner at the Grand Army restaurant in Brooklyn, New York on Sunday (07Aug16), when Zoe turned heads by flashing a large ring on her left hand.

"She had a rock on her finger," a fellow dinner tells the New York Post's Page Six, insisting it "definitely" appeared to be an engagement ring.

The dinner date was not a romantic affair - sources claim the pair met with another woman to discuss an upcoming film project, but the loved-up stars were still affectionate to one another as they sat side-by-side.

"She put her hand on his knee," says another onlooker.

Representatives for Paul and Zoe, both 32, have yet to comment on the engagement claims, but it's not the first time the actress has been seen wearing a piece of jewellery on her wedding ring finger. According to Page Six, she was also photographed with a telling jewel in late July (16).

The couple is known for its low-key relationship, but There Will Be Blood star Dano has previously revealed how he and Zoe have managed to make their romance work, despite their hectic schedules.

"Choose your battles wisely," he advised The Huffington Post in 2012, revealing they like to relax by watching TV - although their programme preferences are very different.

"We're pretty good," he continued. "When she's more busy, I let her put on Project Runway or whatever. But if I'm more busy, I get to watch the (New York) Knicks game so we sort of balance each other out."