Where's Harry Styles? Taylor Swift parties with One Direction stars Louis Tomlinson and Niall Horan

She was hanging out with her new boyfriend Calvin Harris but that did not stop Taylor Swift from being friendly with the friends of her former love interest Harry Styles.

One Direction singers Louis Tomlinson and Niall Horan have been pictured hanging out with the Bad Blood songstress and new boyfriend Harris at a Billboard Music Awards after-party.

In the snap shared by Swift's younger brother, Austin Swift, the Shake It Off singer can be seen laughing around with her DJ beau while Horan, 21, and Tomlinson, 23, pose with props and pretend to pucker up to Ed Sheeran.

There is clearly no bad tension between the two camps but perhaps that is because Swift's ex-boyfriend Harry Styles is missing from the happy photo.

The Steal My Girl singer attended the awards ceremony at the MGM Grand in Las Vegas earlier in the evening but made sure to avoid the after-party at Nobu Villa.

Grammy-winner Swift and 31-year-old Harris appeared to go public with their romance at the awards show when they were spotted kissing.

Hollywood Life alleges the songstress used the PDA to get revenge on her famous ex. A source told the website: "Taylor has never been happier, and last night was her sweet revenge on Harry Styles.

"She was over the moon that Harry was there to witness how crazy she and Calvin are for each other. First of all, she was able to show Harry that, yes, she is completely over him. Second, Calvin rocks her world, more than Harry ever did or could."

The young pop stars dated briefly in 2013 but it came to an abrupt end after spending months being on and off.

The We Are Never Ever Getting Back Together hitmaker was first linked to Scottish hitmaker Harris in February at the Brit Awards in London and have been spotted frequently together since.