Billy Bob Thornton's 14-year-old son is reportedly being questioned by police about his relationship with an older woman.

William Thornton is rumored to be under investigation by Los Angeles police about a possible sexual relationship with a 22-year-old woman. According to gossip website TMZ.com, the lid was lifted on the relationship by the woman's jealous ex-boyfriend, who reported them to police.

Insiders claim police officers are pursuing an "active investigation" into the crime of "unlawful sex" which, in this case, would be a charge of sex with a minor.

Both William - known as 'Willie' - and Billy Bob have allegedly been interviewed by the sex crimes unit of the force.

Billy Bob, now 52, was previously married to Angelina Jolie, who was 20 years his junior.

Willie and his 13-year-old brother Harry James are Billy Bob's children from his fourth marriage to Pietra Dawn Cherniak. Billy Bob also has two daughters, Amanda and Bella.