Culkin and Ruffalo shared the stage in Playwright Horizons' 2000 production of James Lapine's "The Moment When." ...

Kieran Culkin has confessed. The star of “A Real Pain” and “Succession” admitted that he once swapped a prop joint for one ...

Succession’ star revealed that he switched prop joints for the real thing while starring in an off-Broadway production when ...

Kieran Culkin has admitted that he once swapped a prop joint for a real one while acting in a play alongside Mark Ruffalo ...

Kieran Culkin has admitted he's the "naughty young actor" who once got Mark Ruffalo high during a play by replacing a prop ...

After Mark Ruffalo said a "naughty young actor" once got him high on stage when switching a prop joint for the real thing, ...

Kieran Culkin has admitted he mad a ‘stupid’ mistake when he pulled a bold prank on an unsuspecting Mark Ruffalo.

"Mark says, 'I haven’t smoked pot in 10 years; the second half’s going to be so much fun,' " the 'A Real Pain' actor claims ...

Kieran Culkin recalled how he swapped a prop joint with real marijuana while pulling his prank on Mark Ruffalo ...

Kieran Culkin recalled the swapped-joint incident, which went down when he and Mark Ruffalo starred in the stage play 'The Moment When' together when the now 42-year-old Culkin was just a teen.