Cue the awwws!
The 14-year-old gushed about Kim Kardashian's little sis saying: "She's one of my best friends. It's pretty awesome."
So how did the two get so close?
"I was in L.A., we were all hanging out," Smith explains. "Then I went to New York and she came too, and then she came here [to London] and surprised me, so that's pretty baller."
Indeed, the two first made waves when they were spotted on a sushi date at Nobu across the pond.
The cuteness level reached an all-time high as the 15-year-old E! star wore matching leather pants alongside the Karate Kid actor.
For more on Kylie's famous family, tune in to Ryan Seacrest With the Kardashians: An E! News Presentation, April 21 at 9 p.m. on E!