Britney Spears celebrated her 28th birthday with her two sons and boyfriend/agent Jason Trawick.

After a hectic few months on the road with her Circus, the singer kept things low-key with a couple of days spent close to home with the men in her life.

Britney and boyfriend Jason Trawick stroll along Sunset Boulevard, heading to the Chateau Marmont (Splash News)

Britney and Trawick reportedly kicked off the festivities on Tuesday with a pampering session at the Mondrian hotel in Los Angeles, before moving on to the Saddleback Ranch restaurant and the Chateau Marmont.

On Wednesay (her birthday proper) she went shopping at West Hollywood's Fred Segal boutique, and then reunited with sons Preston and Jayden at her Calabasas home.

Britney shopping at Fred Segal on Wednesday (WENN.com)

"Britney looked so happy," an eyewitness told People. "She seemed very excited to spend her morning with Jason."

Another eyewitness added: "Britney is very happy to spend the day with Preston and Jayden. The kids know it's her birthday...[They] are very excited about Britney's cake too."

Britney through the years