Not because he was intrigued to meet and work with Gershon on a revival of "Bye Bye Birdie," though he was. Not because both had built up impressive Broadway credits, though they have.
It was because she had been in "Showgirls."
"I'm fascinated. That's all I care about," Stamos says. "I make her do moves from it. I talk about how it was shot. I talk about what it was like."
A quick refresher: "Showgirls" was the trashy 1995 skin flick starring Elizabeth Berkley as an up-and-coming stripper who elbows her way to the top of a Vegas pole. If you wanted a film with inexplicable nudity, atrocious dialogue, flat attempts at humor and a gratuitous rape, this was the movie for you.
Despite taking a grilling from critics, the film became something of a guilty-pleasure cult flick. Stamos has even hosted "Showgirl" drinking parties at his house.
"There are many drinking games, but it's best to drink as much as you can before you hit 'Play,'" he says, laughing. "That's the game."
So you can imagine how pleased he was to meet Gershon, who played a stripper in the film. "She survived that movie — a lot of people didn't," he says.
Gershon is putting up with Stamos' persistent questions, for now. She's quietly planning her revenge: He, after all, was in something that also became a punch line — "Full House."
"I haven't seen it. It's actually even more insulting, really," she says in a separate interview. "Once I see it, honestly, that's going to be the end of that; there's going to be no turning back. I should probably wait a little bit because I will be shameless, ruthless."
Such gentle offstage teasing will be an asset when the two appear in the first Broadway revival of "Bye Bye Birdie" since the 1960 original introduced songs such as "A Lot of Livin' to Do," "Kids" and "Put on a Happy Face."
The show, produced by the Roundabout Theatre Company, involves an Elvis Presley-like rock 'n' roll star named Conrad Birdie and the effect his being drafted into the Army has on teens in a small Ohio town. Stamos plays Albert Peterson, Birdie's nebbish manager, and Gershon portrays Albert's long-suffering secretary, Rose.
It's Stamos' fourth time on Broadway, but the first time he's originated a part. He replaced Matthew Broderick in "How to Succeed in Business Without Really Trying" in 1996, Raul Esparza as the slithery master of ceremonies in "Cabaret" in 2002 and Antonio Banderas in "Nine" a year later.
"I've come in and replaced three very established, great people on Broadway. I've injected myself into the community. So I feel like I've paid my dues to be able to come and do 'Bye Bye Birdie' now and originate a role," he says.
The musical is Gershon's third Broadway credit, following a turn as Sally Bowles in the same revival of "Cabaret" that would star Stamos a year later, and in last year's "Boeing Boeing."
It turns out that Gershon is an old pro at "Birdie": She appeared in a high school production. Gershon was given the role of Rose, much to her anger. Even back then, she was exploring her edgy side.
"I was obsessed with playing Conrad Birdie, and I couldn't understand why they wouldn't give me that part," she says. "I remember I was 6 inches taller than my Albert, so I had to wear flats. I was really mad about that. I said, 'I want to wear heels!' They said, 'You can't. You're already towering over Albert.'"
Theatergoers might be surprised that Stamos, still boyishly handsome and an accomplished drummer who tours with The Beach Boys, passed on playing the rock 'n' roll star in favor of portraying Albert.
"He's a lot closer to me. He's a sort of fidgety guy, he's a hypochondriac, he's a little afraid of his mother, which is me in real life as well. I'm digging into all that," he says.
Stamos steps onstage trying to shake the long shadow of "Full House," the squeaky-clean TV series that made stars of the Olsen twins but didn't always feed the acting challenges of its adult stars.
Since the show ended, Stamos has appeared in a TV adaptation of "A Raisin in the Sun" and the A&E film "Wedding Wars." His attempts to rejoin a TV series initially stuttered — the comedies "Jake in Progress" and "Thieves" were both yanked early — until he jumped aboard "ER."
"I've always been proving myself. To this day, at 45 — 27 years in the business — I still have to prove myself," he says. "It's maddening sometimes, but it's also what's kept me going."
Gershon's career hasn't missed a beat at all since her first speaking role in "Pretty in Pink," and even her "Showgirls" turn hasn't derailed it.
On TV, she's had recurring roles in "Ugly Betty," "Curb Your Enthusiasm" and "Rescue Me." She's a founding member of the New York-based theater company Naked Angels, played a rock star in the indie "Prey for Rock & Roll" and was in "In Search of Cleo," a one-woman show about the disappearance of her cat that inspired a CD. She has played Jew's harp on recordings for Herbie Hancock, the Scissor Sisters, Rufus Wainwright and Christian McBride.
She's currently writing a sequel to "Camp Creepy Time," a young adult horror-comedy book she wrote with her brother, and recording an album for 3-year-olds called "The Good, the Bad and the Hungry." She's also just finished filming a Lifetime movie about a sociopath.
"What can I tell you? I'm a multitasker," she explains. "I'm a Gemini. I like doing lots of things."
For the near future, she'll mostly be singing and dancing with Stamos — as long as he can get over "Showgirls."
"She's got a lot of fire," he says, devilishly. "I think there's going to be great chemistry."