Toby Willis, star of US reality show The Willis Family, has been arrested on a charge of sexual activity with an underage girl in an incident which allegedly took place 12 years ago.

Family patriarch Willis, 46, was arrested in Greenville, Kentucky, reported WREG Memphis.

Investigators started looking into the case in August. They quickly "developed information Willis had a sexual encounter approximately 12 years ago with an underage female," according to the Tennessee Bureau of Investigations in a statement.

Willis has been charged with one count of rape of a child, and is being held in a county jail without bond.

TBI said officers are still investigating the case, which remains "active and ongoing."

He will be extradited to Cheatham County in Tennessee, where he will be jailed without bond, authorities said.

The Willis Family reality show was screened by TLC, and showed Willis and his wife as they pursued a music career with their 12 children.

"We are shocked to hear this news," TLC said in a statement. It said it had not renewed the show, and no new episodes had been shown since April.

On Saturday (10 September), The Willis Family page on the TLC website had been removed.