It seems pop princess Britney Spears went low key for her 30th birthday on Friday.

According to People.com, Spears spent her birthday ice-skating in Houston with her handsom boyfriend Jason Trawick.

Though the pop star kept the day private, her Hollywood friends were sending birthday messages -- soem welcoming her to the 30's club. 

Happy birthday to the beautiful Miss Britney Spears! Welcome to the 30's club, Brit!! Kim Kardashian said on Celebuzz. I wish you all the best for this next year and beyond. You're going to love your 30's! I love you and hope you have a magical day. 

According to People.com, Spears received phone calls from mega stars Lady Gaga and Justin Bieber on Friday. The magazine also reported that Nicki Minaj, Lance Bass and hundreds of fans posted videos in honor of Spears' birthday.

7 years and so many frosted tips later, we're both finally 30! Ryan Seacrest wrote, posting an old photo of himself with the singer.

But the pop star took time out to thank many of her friends and fans who sent her birthday shoutouts on Twitter

Such a nice surprise! Thank you Heidi for the shout out. So sweet. Xxoo, she wrote to model Heidi Klum.

Thanks Dog! So sweet and unexpected. Xxoo, she responded to Randy Jackson.

Awww, u cute ladies from Hong Kong! http://youtu.be/CIJ5hNrfZjY, Spears said of this video.