LENOX -- Everyone in the opera world knows a Raquel De Angelis, says opera megastar soprano Renée Fleming.

De Angelis is the celebrated diva Fleming will be playing in the world premiere of "Living on Love," beginning July 16 at Williamstown Theatre Festival, where it is scheduled to run through July 26.

"Of course," Fleming said with a laugh during a telephone interview, "I never managed to be that myself. I would love someday to be the subject of dinner table conversation."

Directed by Tony Award-winner Kathleen Marshall and written by Joe DiPietro from a 1985 comedy, "Peccadillo," by the late Garson Kanin (his last), "Living on Love" is about the diva wife of an egomaniacal maestro who becomes infatuated with the attractive young woman he has hired to ghostwrite his autobiography. The diva, Raquel, gets some of her own back by hiring an exceedingly handsome ghostwriter of her own to chronicle her life in opera.

"Living on Love" is something entirely different for the woman who will be opening the Boston Symphony Orchestra’s 2014 season at Tanglewood Saturday evening with a two-part program of American music. The first half, conducted by William Eddins in his BSO debut, features music by Aaron Copland, Samuel Barber, John Adams and Joseph Schwanter.

The second half, conducted by Rob Fisher (also in his BSO debut), artistic director of City Center’s "Encore!" series in New York, draws from Broadway with songs by Rodgers and Hammerstein and by the Gershwins.

The concert fits comfortably into Fleming’s wheelhouse. She has been a champion of American music for some time.

"This program has something for everyone. When I think of Tanglewood, I think of Copland and I think of (the place) as a home for American music."

"Summertime" from the Gershwins’ "Porgy and Bess," one of the songs she will sing in the concert’s second half, is a popular staple of her tours.

The Rodgers and Hammerstein songs -- she’ll be singing from "The King and I," "South Pacific" and "The Sound of Music" -- are particularly satisfying, Fleming says.

"Their songs are such a joy to sing," she said.

"The thing about Rodgers and Hammerstein is that they address so many difficult issues. They didn’t shy away from important things."

If the Tanglewood program traverses familiar territory for Fleming, "Living on Love" does not.

"This is a real departure for me," she acknowledged.

She had scheduled a reading of A.R. Gurney’s "Love Letters" with Alec Baldwin as a benefit for Carnegie Hall last winter when Marshall reached out and asked Fleming if she’d be interested in doing a private reading of "Living on Love" beforehand.

Kanin originally wrote "Peccadillo" for his actress wife Marian Seldes.

"It was very different from what it is now," Fleming said

The reading was "fun," Fleming said, and enough of a success to justify putting the play on its feet.

What happens after Williamstown?

"We are taking our time with this," Fleming said.

The internationally renowned opera star is at a sweet spot in her career. She can do pretty much anything she wants and she is taking advantage.

Fleming is scheduled to do "The Merry Widow" at the Metropolitan Opera in late fall / early winter. She’s been doing a lot of concert tours. She had just returned from a tour in Japan before coming to the Berkshires two weeks ago to begin rehearsals for "Living on Love."

For Fleming, "Living on Love" is "new and exciting.

"I enjoy what I do," she said simply. "All the hard work has paid off and now I’m cherry picking what I want to do."