John Stamos is denying that he ever had a romantic encounter with Allison Coss back in 2004 ... when she was just 17 years old.
Coss, along with Scott Sippola, are being accused of trying to extort $680,000 from the Full House actor by threatening to expose pictures of Stamos allegedly with strippers and cocaine. The two are being charged with conspiracy to commit extortion and are currently on trial.
However the big issue is whether Stamos had an inappropriate relationship with a then 17-year-old Coss. At the time in 2004, he was separated from his then-wife, Rebecca Romijn.
In the opening statements, Coss, now 24, says that she met the actor in Orlando, Florida during spring break ... when he invited her and a friend to his hotel room. Coss goes on to say that Stamos ordered her a drink, kissed her on the bed, took off his clothes, took her into the hot tub and offered to give her oral sex. She says she declined. According to Florida law, it's a second-degree felony for someone 24 or older to have oral sex with anyone 16 or 17 years old.
Also during this alleged encounter, Coss says Stamos, 46, ordered two strippers to come to the room and cocaine was present. That's when she says she snapped a picture of Stamos bending over a table in which the white powder was laid out.
Even though Coss admits that the two never had sex, she says they had a "flirty kind of relationship" via e-mail that went on for years.
Stamos' attorney, William Sobel, denies these allegations and says that the pictures do not exist. In a statement, he says, "The allegations made today in the courtroom by the defendants' attorneys during opening statements will not be proven because they are simply untrue."
Stamos is expected to testify during the trial.