Exclusive: Stephen Collins Faye Grant Asked Witness to Lie About Molestation

Stephen Collins' estranged wife tried to persuade a witness to make false claims about sexual molestation to authorities, and when the witness refused she retaliated against that witness ... this according to Collins' lawyer.
Attorney Mark Vincent Kaplan tells TMZ ... the would-be witness will testify in the upcoming divorce trial. Kaplan claims Grant wanted the witness to claim he/she saw Collins molest a girl -- not one of the 3 mentioned in the audiotape.  Kaplan says the would-be witness saw no such sexual contact, and when that person refused to testify Grant went on the warpath.

A source connected with Collins also tells TMZ ... during the divorce trial his lawyer will attempt to paint Grant as a fraud. She claimed in legal docs Collins left her destitute, but the source says she was actually blowing between $20K and $40K a month on her credit cards and Collins paid the bills.