Britney Spears is engaged.

The pop star's boyfriend Jason Trawick was expected to propose tonight, but surprised her by doing it last night, and will celebrate her saying yes by throwing a huge party at the Chocolate Lounge and Sugar Factory in the Paris Hotel in Las Vegas.

"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(sic)," she wrote on her Twitter.

At the party will be a giant chocolate fondue fountain and chocolate truffle cigars, before they will head off to the Chateau nightclub, TMZ.com reports.

Jason - who has been dating Britney for two years - asked permission from her father Jamie before getting down and one knee. The singer, who has been married twice before, will need to get a judge to formally sign off the marriage as she continues to be under the conservatorship of her father after a public breakdown more than three years ago.

"When Britney does get engaged, her father's attorneys will notify the judge in her conservatorship case. It's extremely within the realm of possibility that the conservatorship will end, and then Britney will get married. It will be a very smooth transition," a source said previously.

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