Horan, 19, and his One Direction bandmates Zayn Malik, 19, Liam Payne, 19, Harry Styles, 18, and Louis Tomlinson, 20, were on the Late Show With David Letterman in New York City to chat about touring, teenage girls, and trash cans. (According to Tomlinson, a fan in Sweden once slept in a garbage bin hoping to meet the boys.) Hoffman, 75, had been on the show earlier and was still hanging around when the group came out to do their interview.
As the boys took their seats on a special couch Letterman had brought on set for them, the Rain Man actor lingered a little to the side, looking for a place of his own to sit. When there wasn't one, he perched himself on the arm of the sofa and leaned in to Horan, who was sitting closest to the end, before covering the teen's mouth with his hand and giving him an exaggerated (fake) smooch.
The crowd went wild as Horan flailed his arms good-naturedly. ("He told me he was going to do it," the singer said afterward.)
The One Direction guys have had a busy week in New York. Also on Friday -- just five nights after taking the stage at Madison Square Garden -- the band kicked off Z-100's Jingle Ball, which featured performances from fellow teen idols the Wanted and Justin Bieber. But it hasn't been all work and no play for the boys. On Sunday, Dec. 2, Payne enjoyed a holiday date night with ex-girlfriend Danielle Peazer. And on Thursday, Dec. 6, Styles hit the town with new loveTaylor Swift and her BFF Emma Stone.