Taylor Swift and Calvin Harris, pictured here at the 2015 Billboard Music Awards, celebrated her birthday on December 13, 2015 Credit: Kevin Mazur/BMA2015/WireImage

Taylor Swift celebrated her 26th birthday with boyfriend Calvin Harris on Sunday, December 13, at a huge, Christmas-themed party.

The bash, which was held at Apple executive Jimmy Iovine's Malibu home, served many purposes, being a holiday party and a birthday celebration for both Swift and Iovine's daughter Jessica.

"Taylor was given a cake and they sang 'Happy Birthday,'" one source tells Us Weekly of the festivities. Swift's boyfriend Harris and her mom, Andrea Swift, were also present at the lavish yuletide party, along with a couple of other high profile names.

"Gwen Stefani and Blake Shelton were there and they looked really, really cute," our spy continued.

Several photographs of the amazing party showed up online shortly after the party finished.

Jimmy's son Jamie Iovine shared a hilarious selfie of hanging out with the "Bad Blood" birthday girl and her Scottish boyfriend.

He also shared pictures of a giant real-snow ski slope, reindeers, penguins and a Santa's grotto, complete with Santa and Mrs. Claus.

In a snapchat video, shared by DJ Snake, Swift and Harris and DJ Snake are shown snuggling up to Santa while they pose for photographs.

Swift’s birthday celebrations were particularly apt since she and Jimmy Iovine are teaming up for a new project together. As a birthday treat for her fans, the Grammy-winning singer announced that next weekend, on Sunday, December 20, a film version of her 1989 World Tour will be released via Apple Music. 

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