Britney Spears threw a huge joint birthday party for her sons on Saturday (15.09.12).

The singer's boys both had birthdays last week - with Jayden James turning six on Wednesday (12.09.12) and Sean Preston turning seven on Friday (14.09.12) - so she hired the Sky High arcade and trampoline park in Calabasas, California, to celebrate.

Around 20 of the boys' friends were at the party, as well as Britney, her fiance Jason Trawick and father Jamie Spears. It is not known if the children's father, KEVIN FEDERLINE, was at the bash.

The group enjoyed playing games and cake, but presents were all opened back at home.

A source told E! news: ''Britney was smiling ear-to-ear during the whole party and enjoyed watching her kids play with their friends. It was a really lovely occasion; everyone was in a good mood and in the spirit of the birthday. She looked overjoyed and at one point was singing happy birthday to them.''

''Jason and Britney were beaming and couldn't have been more proud of Jayden James and Sean Preston.''

Britney - who is a judge on 'The X Factor' USA was said to be originally planning to marry Jason this year, but has since put the wedding date off until she knows what type of ceremony she wants.

A source said: ''She just isn't ready to commit to concrete plans, because she's not sure what the right thing to do is. She's confused. This is her third wedding, so she doesn't know whether she should go really big and make a huge statement or just do it super toned down.''

Britney was previously married to childhood sweetheart Jason Alexander, although their marriage was annulled after just 55 hours in January 2004. She was then wed to dancer Kevin between 2004 and 2006.