Allison Coss and Scott Sippola were arrested in December (09) after they allegedly threatened to release snaps of the actor with cocaine and strippers unless he handed over $680,000 (£453,000).
On Thursday (15Jul10), Coss, 24, and Sippola, 31, were found guilty of conspiracy and using emails to threaten a person's reputation.
The ER star maintains he did not use cocaine or act inappropriately, and he has now slammed Coss and Sippola for fabricating "slanderous allegations" about him.
In a post on his Twitter.com account on Friday (16Jul10), Stamos writes, "I am shocked and perplexed how individuals could fabricate so many false stories in an effort to defend a crime. I agreed to be a witness for a federal criminal prosecution and endured countless false accusations about my behavior and appropriateness. The allegations made regarding an inappropriate relationship are completely untrue. These slanderous allegations to smear my reputation were part of their defense to redirect attention away from the federal crime of extortion.
"There was no hot tub, no drugs, no nudity and nothing sexual in nature involved in my friendship with this woman. They lied about everything from a pregnancy to compromising photos."
Coss and Sippola, who are awaiting sentencing, both face five years in prison.