(Cover) - EN Showbiz - Britney Spears' boyfriend is planning to propose tonight, it has been reported.

Marriage rumours have been circulating the singer for months, after Jason Trawick was spotted visiting jewellery shops. The pair have been dating since 2009 and it is believed they will get engaged this evening.

"Multiple sources who are definitely in the know say Jason's plans to pop the question tonight... in Las Vegas," reports TMZ. "We're told Britney knows they're getting engaged, so it's not going to be a big surprise."

The pair are in Las Vegas to celebrate Jason's 40th birthday.

Jason has reportedly stuck to tradition and asked Britney's father Jamie Spears for his consent to marry the star. Jamie shares a close bond with Jason and he has given the nuptials his blessing.

Their marriage plans will also need to be approved by the judge involved in Britney's conservatorship case, but this is not thought to be a concern.

Jamie is still in charge of her personal and professional affairs following her 2008 meltdown. If Britney does intend to marry Jason, it has been reported that her conservatorship could finish.

TMZ also claims that Britney and Jason will sign a pre-nuptial agreement before their wedding.

During a recent radio interview, Britney's slip of the tongue revealed her commitment to Jason.

"Actually with my I was going to say my husband boyfriend we do that," she said while sharing a story about costumes.

This will be Britney's third marriage.

The 30-year-old has two boys from her three-year marriage to Kevin Federline. She also had her 55-hour union to childhood sweetheart Jason Alexander annulled in 2004 after the pair wed in Las Vegas. (C) Cover Media