Kieran Culkin Confesses He's The Actor Who Pranked Mark Ruffalo, Got Him High On Stage

Kieran Culkin got Mark Ruffalo high on stage over 20 years ago!

The 42-year-old A Real Pain star recently confessed publicly to a prank he played on his former co-star when they starred in a production of the play The Moment When together in 2000.

Previously, Mark revealed a “naughty young actor” got him high on stage during one night after they switched a prop joint for a real one, and now Kieran has come forward with being responsible.

Keep reading to find out more…

“I was 17 and stupid,” he said during an interview with The Guardian.

Kieran revealed that there was a bag of fake joints and he found it too tempting not to switch one of them, and he found weeks later that the real one he switched was being used when he caught the smell and thought, “Uh-oh. I believe it’s happened.”

He then ran to the wings and watched as Mark took big puffs of it before passing it to a co-star during the play, but by intermission, he had to come clean.

“I’m like, ‘I thought this was a good prank. I’m stupid. Oh my God, I’m so sorry.’ But actually, they loved it. Mark says, ‘I haven’t smoked pot in 10 years; the second half’s going to be so much fun,’” he said. “There was this other actor who had never smoked pot in her life. She goes, ‘Is this what being high is? This is lovely.’ And then Phyllis Newman comes in and goes, ‘I haven’t smoked pot since the 1960s. Thank you, darling.’”

“Then the stage manager comes stomping in and goes, ‘I don’t care whose it is, or what happened, but Kieran, give me the joint. I sheepishly handed her the roach and she said, ‘Ruin your life on your own time,’” he added.

Mark opened up about the moment during an appearance on The Graham Norton Show in 2012.

“There was a play that I did that I had to smoke a joint in the first scene. And of course, there was a very naughty young actor I was in the play with, who on the opening night with all the critics, he slipped a real joint onto the prop table,” Mark dished.

The actor added that he tends to “overdo everything” when acting on stage, saying, “So, when you’re out at a party, you take two puffs and you say, ‘Okay, that’s enough. I’m so stoned.’ But I was acting, so I was just like—”

“Between the two of us, we smoked a giant blunt on stage,” he went on. “And I’m like, ‘Man, I am in it tonight. I feel it. I’m on fire. I’m feeling it… why’s that dude standing backstage laughing at me?’ And the kid who put the joint on the prop table is standing there, [laughing]. And I just went, ‘Oh s—.’ But at the end of the play, I got the best reviews of my entire career.”

Recently, Kieran revealed the one thing he doesn’t like about being a dad…