Taylor Swift opted to not attend the 21st birthday bash of her BFF Selena Gomez, reportedly because of her on-again, off-again beau Justin Bieber.

According to Perez Hilton, a source explained, “Taylor isn’t mad that Selena’s party was in LA. Taylor has been busy and will celebrate with Selena sooner than later and has contacted her to wish her a Happy Birthday, but she would have avoided going to the party because she would know Justin was there and she isn’t a super partier.”

The source continues, “She is actually happy that she was busy so she had an excuse to avoid the hoopla herself as she would avoid the drinking and the carrying on.Taylor is very much a homebody and a little reserved so she is not to torn up that she missed out.”

Swift, who is notorious for slamming her ex boyfriends in song, is probably even happier that she missed out on the festivities after it was revealed Gomez had a picture of Bieber designed on her cake.

This isn’t the first time Swift has expressed her displeasure for Gomez dating the controversial Bieber. The “I Knew You Were Trouble” songstress mocked the “Baby” singer backstage at the Billboard Music Awards and even stuck her tongue out when she saw Gomez talking to her former flame.

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