A PORN star and her X-rated director boyfriend sexually abused a young girl over a four-month period, police say.

Melinda Smith - who performs under the name Mercedes Carrera - was charged on Tuesday in Rancho Cucamonga, California with eight counts of sexual acts against a child under 10.

The 36-year-old was charged alongside partner Jason Whitney, 43 - who goes by the name Daemon Cins in the porn industry.

Smith promotes herself as a "lead MILF" on adult sites and also touts herself as a free speech activist.

The couple's bedroom was set-up so they could film pornographic videos and web shows, police say.

Officers executed a search warrant at their home on Friday after the sex abuse allegations were reported on January 31.

COPS 'FIND GUNS AND DRUGS'
In interviews with the young girl, detectives heard that she had been abused by Smith and Whitney over four months.

Rancho Cucamonga Police said: "The sexual abuse consisted of inappropriate touching, oral copulation and digital penetration".

Officers searching the couple's home also found methamphetamine and two loaded handguns.

Police say they believe the couple may have abused more "victims".

Alongside the sex abuse charges, the couple have been charged with one count of possession of a controlled substance while armed with a handgun.

They have been denied bail and remain in custody.

Anyone who has additional information is urged to contact Rancho Cucamonga Police Detective Bureau.