Jennifer Aniston is reportedly making sure John Mayer doesn't slip through her fingers this time by proposing marriage.

The couple - who officially separated in August – are said to be rekindling their romance after two months apart from one another.

A US publication reports that Jen is looking to seal the deal with her on-off boyfriend so their union is official and John cannot walk away.

A source tells Star magazine, "John sent Jennifer a series of romantic emails - but she said she would only take him back if they got married, and he agreed.

"They both know this is it. She wants to settle down, and finally, so does he.

The source adds, "They've even talked about having a family, and John said that he couldn't imagine doing it with anyone but her.

'Johnnifer' were recently rumoured to have a baby on the way.