Although they claim they are just friends, the romantic relationship between Harry Styles and Kendall Jenner seems to be only budding, especially after making their midnight memories in London over the weekend.

The Keeping Up with the Kardashians reality star apparently was in London, as she took Instagram to post a snapshot of herself posing beside the River Thames on Saturday. She captioned the photo, "hey Ben!" with Big Ben in the background.

While Jenner was enjoying London's skyline, One Direction attended the annual NRJ Music Awards at the Cannes Festival Palace in the southern French city. The band received two trophies at the prestigious event -- Video of the Year for "Best Song Ever" and the International Duo/Group of the Year.

Just few hours after, Harry Styles left his bandmates behind, and quickly flew back to London to see his latest love interest. Clad in black jeans, matching t-shirt and jacket, and red checkered-shirt, the 19-year-old singer spotted solo sneaking into the hotel where Jenner was staying at 2:20 a.m. on Sunday.

According to a source close to the Kardashian family, Kendall Jenner reportedly spent two years plotting to steal the heart of the British cutie. "Kendall wanted to make the move on Harry from day one but she was advised by mutual friends he wouldn't be interested until she turned 18," the source said. "The reasoning was that while she was below 18, she'd be too close to the age range of 1D's hardcore fans, who are mainly young teens."

The source continued, "So Kendall patiently waited until she hit 18 to get in touch with Harry, which she did shortly before the band came to L.A. last month. And Harry jumped at the chance to meet up with her."