BRITNEY SPEARS is tying the knot with her longtime love — and former agent — JASON TRAWICK!

Jason, 40, popped the question to the pop princess, 30, furing his birthday party Thursday night in Los Angeles.

Spears tweeted on Friday, "OMG. Last night Jason surprised me with the one gift I've been waiting for. Can't wait to show you! SO SO SO excited!!!! Xxo." The couple, who have been dating since 2009, are heading to Vegas to celebrate this weekend.

Spears has two sons, Preston, 6, and Jayden, 5, with ex-husband KEVIN FEDERLINE, whom she divorced in 2006.

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