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 ...