Christina Aguilera has marked her 32nd birthday with a surprise bash at her Beverly Hills home.

The singer, who attended the wrap party of the US version of The Voice earlier this week, returned from a spot of Christmas shopping to find 20 close friends singing Happy Birthday as she walked through the door, Us magazine reports.

Celeb pals including Nicole Richie and Blake Shelton were in on the surprise, and Christina's boyfriend Matt Rutler had decorated the home with "tons of balloons", according to a source.

The mum-of-one - who also received a tasty two-tier black, pink and white cake - was said to be "completely surprised" and "very happy" about the birthday treat.

Guests munched on finger foods such as mac n' cheese, mini chilli dogs, devilled eggs and grape leaves.