Billy Bob Thornton claims his marriage to Angelina Jolie ended because he was ''too insecure''.

The 56-year-old actor - who split from the 'Salt' actress in June 2002 - said their relationship failed because he ''didn't think [he] was good enough for her''.

Speaking on ABC's 'Nightline' programme, Billy Bob confessed: ''I blew it because I didn't think I was good enough for her. She has one way she wanted to live her life and I had another way to live mine and I was just too insecure.''

The Oscar-winning 'Sling Blade' director admits he particularly found Angelina's rise to super-stardom difficult after she landed the lead role in the 2001 blockbuster 'Lara Croft: Tomb Raider'.

He revealed: ''When you're in a relationship and it's two celebrities, or whatever, I think that puts on a lot of pressure. When Angie and I got married, during that time, I was more famous than she was to start with and then when she becomes this big thing, it's hard in these relationships.

''I did feel like the Phantom Of The Opera hiding in the catacombs. People have actually said that I didn't deserve to be with her.''

Despite their separation, the former couple - who met in 1999 on the set of 'Pushing Tin' - have remained friends.

Billy Bob added: ''We had a great marriage and I chickened out because I didn't feel good enough. That's all that happened. It was no big deal, we never hated each other.''

Angelina, 36, is now engaged to Brad Pitt, 48, and the pair have six children, Maddox, 10, Pax, nine, seven-year-old Zahara, Shiloh, five, and three-year-old twins Knox and Vivienne.