Angelina Jolie helps ex husband with autobiography

The star writes foreword for Billy Bob Thornton's book

They divorced in 2003 after three years of marriage, but Angelina Jolie has gone to prove there's no bad blood between her and ex husband, actor Billy Bob Thornton.

The Oscar winner has in fact written a forward for Thornton's autobiography, The Billy Bob Tapes: A Cave Full of Ghosts.

In the forward obtained by US magazine Life & Style Jolie praises her ex husband, saying he has a big heart and an 'unmatchable wit'.

'I know one thing: The world would certainly be a hell of a lot more dull if that man weren't in it.' Jolie's written in the foreword.

The mother of six is also featured in the book, in the chapters relating to her relationship with Thornton.

The pair met on the set of film Pushing Tin in 1998 and married two years later.