According to TMZ, insides have said that Trawick will pop the question in Los Angeles later today (December 16).
Spears confirmed that she was dating her ex-manager in May 2010. Speaking earlier this year, the 30-year-old said that she and Trawick were "comfortable being ourselves" together, adding that she would "never say never" to marrying him.
Sources claim that Spears knows of the forthcoming proposal, while Trawick sought permission from Spears's father Jamie. Meanwhile, the plans will also reportedly need to be approved by the judge in her conservatorship case.
Previous reports of an engagement were dismissed by Spears's UK publicist earlier this year.
Trawick starred alongside Spears in the video for her most recent single release 'Criminal'.
The Femme Fatale star married dancer Kevin Federline in 2004. The couple divorced two years later, following the birth of their second child.
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Watch the 'Criminal' video below: