Credit: Dimitrios Kambouris/; Jamie McCarthy/Getty Images for MTV (2)

You could've cut the tension with a knife. After Taylor Swift appeared to bad-mouth former love Harry Styles at the MTV Video Music Awards in Brooklyn on Sunday -- mouthing "shut the f--- up" as the One Direction heartthrob was onstage -- the exes came face-to-face at a private after party. In fact, the twosome even posed for a photo together, with party promoter DJ Spiky Phil and mutual pal Ed Sheeran between them. (The post-VMAs bash in question was held at the SoHo Grand Hotel Club Room in Manhattan.)

A source tells Us Weekly that the close encounter between Swift, 23, and Styles, 20, was "super awkward," and that amiable singer Sheeran, 22, was something of a peacemaker. "Ed made sure to keep them separate," the source continues. Another pal has said that the redheaded "Lego House" singer, close with both Swift and Styles, is often forced to play "Switzerland" when it comes to the pair, who split in January after a few months together.

During the VMAs show itself, Swift (ultra-glamorous in a sexy gown from Herve Leger by Max Azria and Prada heels) and Styles sat just rows apart, and did not make eye contact inside the auditorium. But Swift's disses that night weren't just aimed at Styles; accepting her Best Female Video trophy for "I Knew You Were Trouble," quipping, "I also want to thank the person that inspired this song, and he knows exactly who he is!" Released in October 2012, the track is presumed by many to be about her late 2011 flame Jake Gyllenhaal.

Said Styles' One Direction bandmate Liam Payne of the jibe: "I just thought it was a bit not needed. I mean, you just won an award, it's like, concentrate on yourself!" Payne also agreed with a reporter's assessment that Swift's VMA tude was "lame."