The 'Never Say Never' hitmaker managed to convince the singer she'd ruined a couple's big day in an episode of prank show 'Punk'd' - on which he has replaced Ashton Kutcher as host - after inviting her to his house to write a track with him.
A source told Hollywoodlife.com: "Justin called Taylor Swift and asked if she would come over to his Beach House and help him write a song for Selena Gomez. Taylor agreed and even asked him to open for her at her show that night in Los Angeles."
While they were at his house, Justin convinced Taylor to set off some fireworks with him, one of which 'accidentally' landed on a boat which was hosting a wedding party, setting fire to it and meaning the guests - who were all actors - had to swim to shore.
Taylor was unaware of that fact it was all an elaborate stunt, leaving her distraught, until Justin revealed she was on the show.
The source added: "Taylor didn't start crying but was very freaked out and was like 'OMG I'm so sorry! Justin was trying to downplay the situation, When he said she'd been punk'd she started laughing and said, 'How could you do this to me?' (sic)"
The pair made up, however, and Justin later joined Taylor at the Staples Center in Los Angeles, where they performed his hit 'Baby' together.
Taylor later tweeted: "You think you've heard LOUD screaming in your life.. Then @justinbieber comes out and does a surprise song during your show. Woah. Unreal.(sic)"