Britney Spears is itching to be reunited with her two sons Jayden James and Sean Preston after a gruelling week in Europe to promote new album Circus.

The pop princess - whose miming on the X Factor on Saturday failed to overwhelm audiences - may have a valid excuse for her half-baked comeback performance - she was reportedly devasted to leave her boys behind.

A source tells Life & Style, "Britney tells the boys, 'Mama has to work' - but they don't really understand.

"Sean is older, so he's a little more independent, but when it's time to leave Jayden always cries."

The source adds, "She's clearly sad about having to leave them to go back to work."

See Britney at JFK airport on route to meet up with her sons who touched down in Newark into the arms of Meemaw & Peepaw Spears