Actor and playwright David W. Dietz III has a lot going on this summer.

The 34-year-old Crafton resident will make his Pittsburgh Public Theater debut next month, portraying a page in "Mary Stuart." And on Friday, the curtain will go up on his "The Celestial Social Service," at South Park Theatre. The play is a semiautobiographical comedy that Dietz said he wrote as therapy while trying to get over a lost love.

"The story evolved out of the therapy," Dietz said, "I was pretty broken up over the breakup."

The Dietz family business is in a different line, with his father still running Dave Dietz Florist in McKees Rocks, which his grandfather opened 70-plus years ago. As for Dave III, he said he was bitten hard by the theater bug after playing Nathan Detroit in Montour High School's 1988 production of "Guys and Dolls."

Since graduating from Robert Morris College, the aspiring thespian has appeared in more than 80 productions in summer, local and regional theaters in the area.

"The Celestial Social Service," which is being directed by Christopher Scott, is part comedy and part fantasy. The play, which started life with the somewhat unwieldy title of "The Perfectly Ordinary Tale of Eros' Apprentice," tells the story of a man unlucky in love, who reconnects with a long lost romantic partner and suddenly finds support from a mysterious woman who may or may not be the goddess of love.

Unsure whether he has lost his mind or is simply in an inexplicable situation, the hero carries on to win back "the one that got away."

South Park Theatre artistic director Audrey Castracane said she took a shot at a new play for her season opener because of her faith in the playwright.

"I saw a seated reading [of the play] and enjoyed it," Castracane said, "and Dave has acted here before," she said of Dietz, who starred in "The Odd Couple" and "Caught in the Net" at the theater last year.

As excited as Dietz is to see his play come to life at one of the area's most popular and successful summer theaters, his acting commitment may keep him away from some of the action.

"I don't even think I'll make it to the opening night performance," Dietz said with more than a hint of disappointment in his voice.

But the Public Theater job is also important to the playwright's other dream of gaining an Actor's Equity card, which allows a performer to take roles in professional shows that, for the most part, exclude nonunion cast members. The only way to achieve that goal is by accumulating "points" in minor roles in equity productions such as "Mary Stuart."

Dietz says he is pleased with Scott's cast selection for the South Park production.

Ross Blumen will play the part of the star-crossed lover who is the playwright's alter ego, with Emily Lorini as the object of his affection. The nymph-like Val will be played by former Post-Gazette featured actress of the year, Megan May Mitchell. That choice could not please the author more.

"Val has to be terribly gorgeous and funny. It's hard to find an actress who can be both. Megan can," Dietz said.

Even with a summer full of firsts, Dietz shows no signs of slowing down. He plans to pursue more acting jobs, and his adaptation of the story of Aladdin will close out the South Park Children's Theatre season. He said that he was grateful to Castracane for the opportunity.

"Audrey is an advocate for the playwright," he said.

. South Park Theater is at Brownsville Road and Corrigan Drive in South Park. The performances there of "The Celestial Social Service," are at 8 p.m. on Friday, Sunday, May 27, 28 and 30, and at 4 p.m. and 8 p.m. on Saturday and May 29. All seats cost $10. Call 412-831-8552 for details.