Michael Sheen for the first time acknowledged that he is dating Rachel McAdams on Tuesday, May 17, at the New York City premiere of Woody Allen's new movie, Midnight in Paris, in which they co-star.
Earlier, Sheen and McAdams walked the red carpet together at the 64th Annual Cannes Film Festival for the premiere of "Sleeping Beauty" on May 12.
"We've been a couple for a while now," Sheen told ABC News at the Tuesday event.
Michael, 42, and Rachel, 32, were struck by Cupid's arrow while filming on location in Franc during fall.
"That's where we met...got to know each other," Sheen said.
They didn't start dating immediately.
"Much later on…in her home city of Toronto," Sheen said.
At the premiere, McAdams played coy about the relationship, simply saying the film's cast "got to spend good quality time in Paris… we all had a great time together… "
It was "something I will always really cherish."
Woody Allen says he didn't see the romance coming, unlike in the case of Penelope Cruz and Javier Bardem who became smitten with each other while filming Woody's Vicky Cristina Barcelona in 2008.
"No, I didn't see it coming," he told People. "I could notice it a little with Penélope [Cruz] and Javier [Bardem] – who began dating during the filming of Allen's Vicky Cristina Barcelona. "They were kind of chummy. But I didn't see it coming here ... and they did not ask my permission."
McAdams earlier dated her The Notebook (2004) co-star Ryan Gosling from 2004 to February 2007. They were engaged to be married, but she called off the engagement.
Sheen was married to English actress Kate Beckinsale for seven years (1992-2003); they have a daughter, Lily Mo Sheen, born 31 January 1999.
After his divorce from Beckinsale, he dated ballet dancer Lorraine Stewart from 2003 to 2010.