Jennifer Aniston is insisting on a strict pre-nuptial contract before she gets married to Justin Theroux.

The 43-year-old actress, worth an estimated £80million, is reportedly refusing to marry the director, 41, until he signs the agreement.

A friend of Jennifer told the Daily Star newspaper: ''Jen's thrilled to be getting married but she's leaving nothing to chance.

''She wants to make sure all her assets are protected, especially with her track record with men.''

The 'Friends' star has dated musician John Mayer in the past and her ex-husband, Brad Pitt, recently sent his congratulations on the news of her engagement.

The 48-year-old star spoke with his ex-wife, who he split from in 2005, to say how pleased he was to hear the news she is marrying actor Justin, who proposed at his 41st birthday dinner on Friday (10.08.12).

A source said: ''Brad gave Jen a quick call to say how pleased he was to hear that she was getting married.

''He jokingly asked if he should 'save the date', and they both laughed, but told her in all seriousness that he was really happy for her and Justin.

''He wished her luck and told her he hopes they're very happy together.''