The Insider.com

It's official! Britney Spears and her new fiance Jason Trawick celebrated their engagement at Planet Hollywood Resort & Casino in Las Vegas Friday night, and we have the first pix of the happy couple! For more great shots, head on over to ETonline.

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The singer tweeted, "Tonight was one of the most magical nights of my life. Such an amazing time with my new fiancé and our closest friends and family. #Blessed"

MORE: Britney Engaged!

During the romantic getaway, the couple also celebrated at Sugar Factory American Brasserie and Chateau Nightclub & Gardens at Paris Las Vegas.

Britney and Jason, her former agent, have been an item since 2009, and he reportedly popped the question with a Neil Lane ring Thursday, his 40th birthday, during a romantic private dinner.

"She's really happy," a source tells The Insider. "It's going to be a great weekend."

Stay tuned to The Insider for more Britney news!