John Stamos of Full House fame says he was targeted by blackmailers who threatened to sell so-called "compromising" photos of him unless he coughed up $680,000.

Allison Coss and Scott Sippola of Marquette, Mich., were arrested last week in an FBI sting operation after they met with an undercover agent, posing as a Stamos rep.

The sting went down at a Michigan airport and they got busted.

After police raided the suspects' home, they discovered three John Stamos pics, a piece of paper with the actor's cell phone number on it, and a list of three celebirty gossip magazines with contact numbers for each, according to the affidavit.

If John Stamos can be blackmailed, who among us is safe?

Stamos was vacationing in Florida when he met Coss. At the time, the pair and another pal attended a party where pictures were allegedly taken of the actor.

Following the party, he began receiving email threats from a person who allegedly demanded $680,000 from Stamos or else the pics would be sold to a tabloid.

The affidavit did not describe the photos, but Stamos was told they would "cause harm" to his reputation if released. No word on when the pictures were taken.

Man, $680,000 for compromising John Stamos pics. Imagine what images proving a Tiger Woods overdose (or cellphone shots of the golfer naked) might fetch.