John Mayer has been secretly hooking up with ex Jessica Simpson following has split from Jennifer Aniston, it's claimed.

There appeared to be no love lost when the couple ended their relationship in 2007, with both going on to take thinly-veiled swipes at each other in public.

But, according to a new report, the pair have since kissed and made up to the extent that they are enjoying lunch dates together.

“Jess and John looked so happy to see each other, and it looked to me like they were more than friends!,” a source who spotted the pair having lunch in Calabasas, California, tells X17online.

Back for seconds? John and Jessica in 2007

John this week claimed to be single after splitting with Jen in March, whist Jessica has been dating Dallas Cowboys quarterback Tony Romo for the past eighteen months.

Relive John and Jen's romantic moments below