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As for the funnyman’s highlight of the star-studded Venetian nuptials?
“My favorite part of the wedding was that those two people found each other in life,” Murray told PEOPLE at the comedy-drama’s New York City premiere Monday. “That was my favorite part of the wedding.”
So if Murray were to spend a day with his 11-year-old scene-stealing costar – or someone Lieberher’s age – what would they do? The actor, who was quick to point out he had ample practice with his own six kids, answered practically.
“Well, first, I’d feed them. You have to make sure they’re healthy and fed. I’d take him to this thing [the red carpet], get this over with. And [we’d] probably skip the movie because we’ve seen it so many times by now,” Murray said.
“I’d take him to see another sight in New York, then take him home and see if he had any homework to do. You have to do it that way with kids.”
While Murray would surely have fun with his young colleague, he was also impressed by another costar: Naomi Watts.
“There’s a reason she’s in every movie. Directors love her,” he said of the actress, who plays a Russian prostitute with a heart of gold in the movie. “She’s a dream. No one would have played the role like she did.”
St. Vincent hits theaters Friday.
• With reporting by MAGGIE PARKER