(Cover) - EN Showbiz - Angelina Jolie appreciated the "unmatchable wit" of her ex-husband Billy Bob Thornton.

The actress, who is currently engaged to actor Brad Pitt, and Billy Bob were divorced in 2003 after three years of marriage.

Life & Style magazine reports that Angelina wrote a glowing forward for her ex's new autobiography The Billy Bob Tapes: A Cave Full of Ghosts.

"[Billy] has a big beautiful heart," she penned in the tome. "He has an unmatchable wit and can make you laugh until your face hurts."

The star also admits that Billy was a bit loony at times.

"To be with him is like being with a mad mathematician," Angelina wrote. "He is constantly counting and repeating. Some people walk through life able to quiet the voices in their heads. He can't. And I, and everyone else who knows him well, we love him for it. I know one thing: The world would certainly be a hell of a lot more dull if that man weren't in it."

Angelina and Brad confirmed their engagement in April. The couple have six children together. (C) Cover Media