The on-and-off pair, who were first linked in 2013 and enjoyed a Caribbean getaway together earlier this year, have started dating again, reported People magazine.
"They're rekindling their old romance and Kendall's so excited and happy about it. She's always cared about Harry. Kendall was beaming all night. They're trying to spend time together again," a source said.
Although Jenner, 20 and Styles, 22, have known each other for some time, things apparently never got serious before.