To celebrate their one-year anniversary as boyfriends, Tony Clements and Rob Hancock went out to see a production of Mamma Mia! in their hometown of Milwaukee, Wisc. Now, in their fifth year together, they are performing lead roles in the national touring company of the ABBA-inspired musical, which opens in San Diego Oct. 18 for a two-week run.

“When we came out of the show five years ago, he was being very supporting and said I could play the role of one of the dads,” Clements told the Gay & Lesbian Times. “Of course, I responded by saying that he could easily play Sky, the lead.”

A year after their inauguration to Mamma Mia!, Hancock convinced the begrudging Clements to attend an open casting call. “We both went down and auditioned, and I was the one that got cast,” Clements said. “He joined the cast later.”

After performing in the ensemble for two years, Clements was cast as Sam, one of the three fathers in Mamma Mia! that Hancock predicted his boyfriend was meant to play. A few years later, Hancock auditioned once again to join the ensemble.

“I remember him calling me after the audition, and he asked if I was sitting down. I said, ‘Did you get the ensemble role?’” Clements recalled. “He said, ‘You really need to sit down for this. I got the part of Sky.’”

So for the past few years, the couple has been traveling the country together – with their pet dog, of course – performing in one the most feel-good shows on stage.

“I think the show has just a sweetness that people crave,” Clements said. “Ben Brantly, a critic with The New York Times, compared the show to a Hostess cupcake: It’s junk food, but you really love it. It’s so much fun.”

Told through the songs of ABBA, Mamma Mia! introduces Donna, a feisty 40-something single mom, who recalls memories of carefree days and careless nights, while her daughter, Sophie, dreams of a traditional romance. On the eve of marrying Sky, the local dream hunk played by Hancock, Sophie begins a far-fetched quest to discover the identity of her father.

“She’s discovered, after reading her mother’s diary, that she has three possible dads,” said Clements, who plays one of the possible dads, Sam, the typical arrogant, leads-with-his-pelvis straight man. “So she invites them all to the wedding. Chaos ensues when all three dads show up.”

The story line is secondary to the real focus of the show, Clement said. The plot of Mamma Mia! is just an excuse to dance like a queen.

“Every time I describe the story, I sound so ridiculous … but it’s not that ridiculous,” he said. “It’s not so much about the plot, it’s about the songs.”

The story is intertwined with 22 of ABBA’S best known hits, including “The Winner Takes It All,” “Dancing Queen,” “Take a Chance On Me,” “Super Trouper” and, of course, “Mamma Mia” – and Clements says that every night, everyone’s having the time of their lives.

“The audiences differ from city to city, but they all love it,” Clements said. He explained the demographics of a typical Mamma Mia! audience is quite varied, ranging from housewives to teen girls – and a strong percentage of gay men.

“I’m not sure exactly why there is such a big gay following. Maybe it’s the ‘Dancing Queen’ song,” he said. “It’s definitely the music. We sort of claim it.”

So is “Dancing Queen” his favorite song?

“You would think I would be sick of hearing ‘Dancing Queen’ after listening to it over and over, eight times a week, for the past four years, but that isn’t true,” Clements answered, adding, “My favorite song in the show changes so often. Right now, my favorite is ‘Super Trooper.’”

The storytelling magic of ABBA’s songs propels this tale of love, laughter and friendship. It helps solidify the show’s theme of enjoying the moment, and being happy with what you have in your life now.

“From my character’s perspective, I show up and I think I have a daughter,” Clements said, not actually revealing if he is the real father or not. “And I talk to her and say to her, ‘Before you make this huge decision in your life, take a moment and think about it.’ She does look around and realizes she has it good.”

And Clements sure has it good. He is able to perform in a show with his committed boyfriend (their sixth show together, by the way) while touring the country together.

“We’re so lucky that we have this job,” Clements says. “We’re just amazed that it happened.”

To see Clements, Hancock and the entire touring cast, get your tickets to see Mamma Mia!. The show opens Oct. 18 – the fourth anniversary of the show on Broadway, coincidentally – and runs through Oct. 30 at the San Diego Civic Theatre. Tickets are $35-$89, and are available by calling the box office at (619) 570-1100 or Ticketmaster at (619) 220-TIXS. To purchase tickets online, visit www.broadwaysd.com.