- Photo: Palace Lee/PacificCoastNews.com1 of 4
"They're dating," says a source close to Jenner, 15. "It's new, but they've been friends forever."
The young stars were most recently spotted together on a lunch date at Cafe Nero in London's famous Piccadilly Square on Sunday. Jaden -- who next appears in the movie "After Earth," opposite his famous dad, Will Smith -- was in town to celebrate his pal Justin Bieber's 19th birthday.
The March 1 bash at Cirque du Soir was cut short, however, after Bieber's posse got into a scuffle with club security; underage Jaden's presence "caused problems," a source told Us, though Bieber denied those claims via his official Twitter account.
Prior to dating the "Hello" rapper, Kylie -- daughter of Olympian Bruce Jenner and businesswoman Kris Jenner -- was linked to Australian pop star Cody Simpson. She denied the rumors, telling Seventeen in September 2012, "Cody and I are just good friends. We can say that as much as we want and people will still listen to gossip."
Keep clicking for more photos of the teens in London ...
- Bikini BurnsFrom Kim Kardashian to Jessica Alba, see the worst celeb sunburns.Watch Video »
- Double TroubleFrom the Olsens to the Mowrys, see some of Hollywood's most famous twins.Watch Video »
- Country CutiesCheck out the hottest couples in country music.Watch Video »
- Crazy QuotesCheck out some of Gwyneth Paltrow's craziest quotes.Watch Video »
From Videos of Wonderwall
From MSN Entertainment
From Crowd Ignite