Stephen Collins -- who played the pastor/dad on "7th Heaven" -- confessed to his estranged wife he was a child molester.
In a tape obtained by entertainment news site TMZ, Collins flatly confesses to molesting an 11-year-old New York girl -- a relative of his first wife -- saying, "There was one moment of touching where her hand, I put her hand on my penis."
He also acknowledges exposing himself to the girl "a couple of times" ... he says when she was 11, 12 and 13.
The New York Police Dept. is now conducting an active criminal investigation involving sexual contact with multiple children.
Collins -- who is in the middle of a nasty, prolonged divorce with actress Faye Grant -- revealed to her in 2012 he had molested and/or exposed himself to several underage girls years before. Collins and Grant went to a therapist where she peppered him with questions about the incidents.
Grant taped the therapy session as her lawyer advised her it was legal to secretly record the conversation because in California you're allowed to do so to gather evidence if the other person committed a violent felony -- and molesting a child under the age of 14 qualifies.
Collins -- who is on the National Board of the Screen Actors Guild -- frequently interacts with young actresses. In addition to "7th Heaven," he was also on the ABC Family show "The Fosters," about a bunch of young kids being raised in a foster family.
And he had a role in the recent show, "Revolution" ... which also had underage actors.