Renee Fleming: Opera is Hard to Sing, Not Hard to Watch. And You Don't Need a Tux.

Renee Fleming loves jazz. She likes pop music, too, though not necessarily in the supermarket.

She sings in both styles, more so as years roll by.

But she remains best known as an opera singer, one of the defining sopranos of her generation, and she'll also tell you that opera is the hardest singing she does. Or anyone does.

"The training for opera is far more challenging," says Fleming. "It's like the Olympics of singing. You have to have the natural instincts and develop them.

"If you're American, you also have to learn to sing in foreign languages, where Germans or Italians can sing in their own language.

"A pop singer can have a great voice and that's all they need. Opera singing is a lot more complicated."

Fortunately for opera fans, Fleming is still doing it. She can also still be seen frequently on PBS, where she's hosting a Great Performances production of Richard Strauss's Elektra featuring Nina Stemme (above) this Sunday at 12:30 p.m. ET (check local listings).

In 2017, PBS will present a new opera that Fleming curated for the Chicago Lyric Opera: Bel Canto, with music by Peruvian composer Jimmy Powers, a relative newcomer. It's based on the book by Ann Patchett, a friend of Fleming's.

Fleming loves the new-blood part of this production. "It's critical that we have new operas," she says. "Otherwise we become a museum."

Not that she's abandoning the classics. She will sing Der Rosenkavalier, one of her signature roles, to close out PBS's Metropolitan Opera 2016-2017 season on May 13.

Fleming admits she's a little surprised that she's still singing soprano roles at 57, since many singers find their voices lower as time passes.

"Placido Domingo is a baritone now," she notes. "He used to be a tenor.

"I thought my own voice would change more. I thought I might become a mezzo. But I'm still holding in the same category."

It would be tempting to say Fleming has also branched out musically over the last few years. Performing for PBS at the Television Critics Association press tour this summer, her numbers included "I Could Have Danced All Night," "Over the Rainbow" and Leonard Cohen's "Hallelujah."

But she's really been singing in other styles all her life. As a music student she was invited to join Illinois Jacquet's band, declining "because I was too shy."

She's sung Christmas songs on The View, performed "You'll Never Walk Alone" at President Obama's first inauguration, sung at Queen Elizabeth's diamond jubilee and recorded with pop singers from Joe Jackson to Michael Bolton. Music fans still talk about her playfully dueling duet with Andrea Bocelli (above).

She has sung The Star-Spangled Banner at the Super Bowl, a top-10 list for David Letterman and various ditties for Garrison Keillor on A Prairie Home Companion. She launched a festival on Long Island this summer with Rufus Wainwright.

"There are some very interesting pop songs today," Fleming says. "Like Abbey Smith on YouTube. My 20-year-old daughter finds a lot of them for me."

The fact that music has migrated to YouTube, of course, underscores some major changes in the whole business, and Fleming says they have a big impact on the music itself.

For one thing, it's tougher to reach or build an audience the way it was done through the whole 20th century, with a physical recording.

"It's very hard today," says Fleming. "It's hard to explain to young singers what I did, because it's not really an issue today.

"There's always room for a star. But getting started is harder now. I've lived long enough to see the business change."

What technology hasn't changed is live performance, though Fleming says the economics have shifted as more performance venues have opened and increased competition has forced some of the larger spaces to scramble for audiences.

She's moved a bit more toward concerts in her personal performance world, she says, and has developed a personal routine that keeps her in form.

"I rest two or three days between performances," she says. She also doesn't talk any more than necessary and she stays hydrated.

"Other than that," she says. "I don't do much. What's most important is vocal technique, and fortunately I had teachers who taught me well."

On the nuts and bolts of the music itself, she says her ear is good, though not all-knowing.

"I can tell if the music is out of tune," she says. "But I can't necessarily trace it to, say, a single violin."

She plays "a little piano and some guitar," and her iPod often includes music she'll be doing at upcoming performances as well as "and some leisure listening" from a range of genres.

What she doesn't want to hear, she says, is "music in the background. Music that's there for no reason is just distracting."

Fleming's music, of course, is just the opposite, and one of the musical legacies she'd like it to leave is moving opera back toward the position it once held - as music for the masses, in the popular mainstream.

Today opera is widely regarded as the musical equivalent of polo -- the province of a wealthy elite.

Fleming would love for that to change, and she hopes opera/pop crossovers like the Three Tenors and her own performances help build a bridge.

"I want to tell people to just go, give opera a try," she says. "You don't even have to wear a tuxedo."