It's been mere hours since Britney Spears accepted Jason Trawick's marriage proposal and the 30-year-old pop superstar can hardly contain her excitement.

"Still glowing!" she tweeted Friday after Us Weekly exclusively revealed that she and her former agent will soon tie the knot.

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The couple plans to celebrate their engagement -- and Trawick's 40th birthday -- Friday evening at Planet Hollywood and Chateau nightclub in Las Vegas.

"About to jump on a plane to Planet Hollywood in Vegas. Throwing a Bday Party for Jason…So fun. Xxoo" Spears -- mom to sons Sean Preston, 6, and Jayden, 5 -- added Friday afternoon.

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A source confirmed to Us Trawick popped the question on his actual birthday, Thursday, when he and the "I Wanna Go" singer shared a romantic dinner. Trawick later confirmed the engagement to Access Hollywood and said he and his bride-to-be are "over the moon."

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"This is something they've both wanted for a long time," an insider tells Us. "It's a way to cement their family. They're both extremely happy and can't wait to become man and wife."

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