LOS ANGELES       -        Taylor Swift was surprised by a belated 30th birthday party in the recording studio.

The ‘You Need to Calm Down’ singer reached the milestone age on December 13, but a few days later, her collaborators Jack Antonoff and Laura Sisk hosted a small celebration to mark the occasion.

Taylor shared a photo of herself holding a birthday cake with Jack and Laura holding balloons either side of her and wrote: ‘’Walked into the studio to a surprise birthday party from these two @jackantonoff& @sharp_stick - it’s equally wild and cozy to think it was the three of us in a room making a song called Lover here last year. [heart emoji].’’

The ‘Cats’ actress had marked her birthday with an ‘’aggressive’’ festive-themed party with friends including Jack, Ryan Reynolds, Blake Lively, Martha Hunt, Camila Cabello, Halsey and Gigi Hadid - with a festive-themed bash, which took place after she’d performed at the Z100 Jingle Ball in New York.

She wrote on Instagram: ‘’Honestly spending my 30th with the fans who have made my life what it is at jingle ball, then throwing the most aggressive holiday party known to womankind ... I just seriously feel so lucky for you all and will spend forever trying to find ways to say thank you. *cries in Christmas tree’’

Taylor previously admitted she is approaching her thirties with a healthier outlook. Speaking before her birthday, she said: ‘’I’m really excited about it. I’ve heard really good things about your thirties. Feeling a bit more secure ... a bit.’’