"Giulietta fits me to a T," says Laura Claycomb, who will open as the heroine of Bellini's "I Capuleti e I Montecchi" at the Benedum Center Saturday evening.

Bellini's setting of the Romeo and Juliet story is an operatic rarity, although its heroine's entrance aria, "O quante volte," has become a favorite audition piece of aspiring lyric and coloratura sopranos. Its libretto was based on Shakespeare's sources, however, not his play, which was virtually unknown in Italy when the opera was premiered in 1830.

Here, for example, Tybalt is Juliet's fiance, while Lawrence is not a friar but a doctor. Another quirk of this version is that Romeo is a "trouser role" for mezzo-soprano -- in Pittsburgh Opera's cast, the popular Vivica Genaux.

By coincidence and odd turns of fate in today's music business, Bellini's Giulietta (Juliet) has become a signature role for the Texas-born Claycomb, who has resided and performed mostly in Europe for the past 14 years. When I first meet her for this interview in the Benedum Green Room, her long red hair is flowing, her willowy frame stretched out on the sofa. There are cartons of fast food on the table. Having arrived late the previous night, she missed dinner on the plane and found no food in her short-term rental apartment. She hasn't eaten for nearly a full day, and says she's ravenously hungry. She offers me some fries and onion rings, and when I politely decline, asks me, with a twinkle in her very bright eyes, "Don't you like fried food?"

The soprano, who will turn 40 this year but looks and acts 10 years younger, first came to international notice in 1994, when she stepped in on short notice to replace established diva Cecilia Gasdia in the role at Opera of Geneva, in Switzerland.

"I had covered [understudied] Gasdia when she did Giulietta at San Francisco Opera, the year before," Claycomb explains. "I was an Adler Fellow at the time, and it was known that Gasdia doesn't like to rehearse. No one was sure whether she would show up at all. Like any young singer, I secretly wished that she wouldn't come and I would get to go on, but she did arrive eventually, and she sang all the performances." It was at the San Francisco Opera, by the way, that Claycomb met Christopher Hahn (now Pittsburgh Opera's artistic director), who became an enthusiastic supporter.

Geneva was a different story. Gasdia cancelled shortly before opening night, and Claycomb, thoroughly conversant with the part by that time, did go on. The event launched her international career.

A year later Claycomb was again asked to cover Gasdia as Giulietta, this time at the prestigious Bastille Opera in Paris. "Gasdia canceled and I was supposed to sing," she says, "but by a stroke of bad luck the technicians went on strike. I didn't do any staged shows, but we were allowed to do what would have been the last performance in concert form, so I managed to make my Paris Opera debut. Finally, in 1996, they hired me -- not as an understudy this time -- and I actually did a fully staged 'Capuleti' at the Bastille."

It's almost shocking to hear Claycomb say of Bellini's Giulietta -- a role that would daunt many a more experienced singer -- that "I never found anything difficult in this opera. Lucia [in Donizetti's 'Lucia di Lammermoor'] is difficult. Zerbinetta [in Strauss's 'Ariadne auf Naxos'] is difficult. Bellini is not as difficult as Donizetti, and certainly not as difficult as Strauss."

But then, she also says, "I'm probably the only soprano who has never sung Musetta's Waltz [from Puccini's 'La Boheme']. I never want to sing Musetta. Puccini is emotionally manipulative ... His operas are not for me. If I have a favorite opera, it's one I'll never sing in, [Janacek's] 'Makropulos Case.' There's no part for me there, but it deals with the meaning of life. That I can get into."

The singer reminds us that Bellini's character is not Shakespeare's Juliet: "This Giulietta doesn't have much joy," she says. "Her music is mostly slow and lyrical. There is not even the typical fast caballetta after her first cavatina. What joy she does have in the opera is always broken up by doubt, as in her duet with Romeo. She is always talking about death, even at the beginning. Romeo has a wider emotional range."