Taylor Swift Gets Birthday Love From Katy Perry, Hayley Williams, Selena Gomez

Taylor Swift turns 21 on Monday (December 13), and she is getting some birthday wishes from many of her celebrity pals, who took to Twitter to show some love to the superstar and send her attention in honor of the milestone.

"Hey!! Today is my girlfrannn @taylorswift13's 21st birthday!!!" Paramore leading lady Hayley Williams tweeted. "Holy heck. She's all growed up. So blessed to know her. Tweet her some love!"

Selena Gomez got in on the action too, writing to her pal, "Happy birthday @taylorswift13!!! I love you so much!!"

Katy Perry also tweeted, "@taylorswift13 happy 21st gorgeous!"

Perez Hilton had a shout-out for Ms. Swift, adding a Latino flair to his wishes: "@taylorswift13 ¡Feliz cumpleaños! #HappyBirthdayTaylor."

Swift got her birthday party started early Sunday, when she tweeted about some festivities that were already under way, sharing that her friends were ringing in another year with the singer.

"Snowflakes are flurrying down outside and it's my last day of being 20!" she wrote. "Tonight @caitlinbird and @elizabethhuett knocked on my door — they brought a pizza with a lit 21 candle on it and bday hats. Now I'm dancing around my room alone to @pink's greatest hits cd."

With her birthday so close to Christmas, the singer revealed to MTV News that she was planning to combine the two celebrations for her birthday party this year.

"The plans for the 21st birthday are probably going to be winter-themed. I love winter. I love Christmas," she said. "When I was a little kid and I was growing up, they'd always have a Santa Claus guy show up and take everybody's wishes or what they wanted for Christmas. I'm not gonna do that, but there'll definitely be lots of Christmas-themed things."

Send your birthday wishes to Taylor in the comments section below!