The 18-year-old E! star spent time with the One Direction hottie backstage at Saturday Night Live on Dec. 7.
A source reveals to E! News that even though the brunette beauty was behind the scenes with the pop star, they did not attend the after-party.
The friendly pair was spotted earlier in the day out and about in New York City, leaving the Gansevoort hotel.
Jenner, who sported a green jacket, white sweater and skinny jeans, tried to keep a low profile with the British singer, but that proved to be a difficult feat when fans swarmed them as they tried to get a bite to eat.
A source tells E! News exclusively that Jenner arrived in the Big Apple for a meeting on Friday, Dec. 5. and added that she and Styles have been in touch for the past several weeks, ever since the American Music Awards.
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The source added that although they were spotted leaving the Gansevoort together, Jenner is staying at a different hotel than Styles.
"I've never seen Kendall happier and more fan friendly," another source told E! News. "They came off the elevator holding hands and then she stood and watched while he posed with fans."
The duo first made headlines after they were spotted stepping out for a dinner date on Wednesday, Nov. 20 in West Hollywood. They were photographed in the singer's black Range Rover after leaving Craig's restaurant at about 12:15 in the morning.
Both have denied that they are an item.
The 18-year-old model told E! News at the AMAs that she and Styles are "friends," adding "he's cool."