If violinist Anne-Sophie Mutter plays Andre Previn 's Tango, Song and Dance with particular affection this afternoon, there couldn't be a better reason: The two are newlyweds.

The announcement of their marriage - Aug. 1, in New York's Central Park - astonished the classical music world. Only insiders had known about their relationship, though the couple wasn't especially secretive.

Ever since their joint tour of Europe with the Orchestra of the Curtis Institute of Music in 1999, their professional paths had crossed frequently. They play chamber music in a piano trio. Mutter gave the world premiere of Previn 's Violin Concerto in March, and will record it this month in Boston. She even built what she calls a "song and dance" program - which she plays today at the Kimmel Center for the Performing Arts - around Previn 's Tango.

Like Arthur Miller and Marilyn Monroe, they seem to be a case of the owl and the pussycat. Conductor-composer Previn , 73, is a reticent, low-key, bespectacled presence on the concert stage. Mutter, 39, is one of the world's greatest violinists, and among the most glamorous, performing in bare-shoulder gowns that also allow her maximum freedom of movement.

Yet such typecasting may not be so clear-cut. Mutter, a widow and mother of two, is more of an owl, having acquired deep analytic skills as a child prodigy that allow her to crack works by fiercely cerebral composers such as Wolfgang Rihm. Previn , who had four previous wives, falls well into the pussycat zone, having grown up in Hollywood writing film scores, romancing movie stars, and pursuing a career as a jazz pianist.

Their effect on each other is already apparent. Mutter's repertoire is now lighter and less brainy, thanks in part to the shamelessly lyrical, lush, improvisational music Previn writes for her. Previn 's new Violin Concerto has greater concentration and consistency than many previous works, more, in fact, than well-known works such as his operatic version of A Streetcar Named Desire.

Together, they still relish calling each other "husband" and "wife. " "A couple days ago," Previn said, "[pianist] Manny Ax, who is a good friend, called to say hello, and she was practicing in the next room. He said, 'Is that your wife playing? Is that cool or what? ' "

The two cuddled on a sofa in a suite at the Lowell Hotel on New York's Upper East Side for an hour on a recent rainy evening and had so much fun that acquaintances confessed to being envious. "Well, you should be," Previn said.

David Patrick Stearns: When studying a piece of music, it can be good to know the composer's personality. You're playing a composer you're married to. Does that allow special insights?

Anne-Sophie Mutter: No. The musician's compositions and private personality have little to do with each other. I don't think I would play the Beethoven Violin Concerto any different if he were my husband.

Andre Previn : I can't cope with that thought!

Mutter: Oh, I would love to have been his immortal beloved.

Stearns: Still, in your case, the composer is at least nearby if you don't understand something.

Previn : There's not that much to understand in my pieces.

Mutter: I disagree.

Stearns: I do, too. And I've always felt that everybody takes Andre Previn 's music more seriously than Andre Previn does.

Previn : There's a certain amount of self-protection in that. I have a lot of commissions [including an opera version of the celebrated Alessandro Baricco novel Silk], and it surprises me a great deal. I very often do not like what I write. People like to play it, but the critics say, "What a load of crap! " It's difficult for me to cope with.

Stearns: Do you approach a piece differently when it's for her?

Previn : I'm more concerned about it, I want it to be especially good. The relaxing thing is that there are no technical difficulties when composing for her. I can write anything. It's wonderful but, in a way, disconcerting: I would love to come up with something where you'd look at me and say, "Are you out of your . . . mind? "

Mutter: I think that, but I don't say it. There are passages in the violin concerto that are so extremely high. It stretches over three octaves.

Previn : You said to me once, "I love playing high. " And I said, Oh-KAY! Within four bars I had her up in the stratosphere.

Stearns: It's such a lyrical piece.

Previn : I wrote it for her.

Stearns: Your recital programs are known to have one musical boulder after another. Your Verizon program is anything but that. There's even Gershwin.

Mutter: I've had my mountain-climbing experiences without an oxygen mask, and it's nice to go back to a program so deeply rooted in violin playing. It's great to give the violin what she deserves - beauty of sound, colors, whispers.

Stearns: Your violin is a "she"?

Mutter: Not an "it. " That's for sure.

Stearns: The Faure Violin Sonata No. 1 is on your Sunday program. I never thought of you playing a composer who is so much about mood and not about rigor.

Previn : You have a treat coming. She plays it better than anybody.

Stearns: Ms. Mutter, your new recording of the Beethoven Violin Concerto takes huge interpretive chances, the sort that one never could've predicted from hearing your first recording, made in your child-prodigy years. What gives you the courage to do that?

Mutter: The personal approach to the piece is the only reason to be a musician. I don't have much time left. That's why the intensity of my music-making is growing.

Previn : You're sitting next to the wrong man to be making that comment!

Mutter: It took me 23 years to rerecord the Beethoven and, after a certain age, it doesn't get any better.

Stearns: You, Mr. Previn , are going to be a big presence in Verizon Hall next month. Your 1973 collaboration with playwright Tom Stoppard, Every Good Boy Deserves Favor, is being done [Nov. 20 through 26] by the Philadelphia Orchestra and the Wilma Theater. When first written, it was a virulently anti-Soviet piece about a dissident who is declared insane and incarcerated for speaking his mind. Yet it has outlived its topicality.

Mutter: We still have regimes like that. They've just changed countries.

Previn : The piece has had a life way beyond mine or Tom's expectations. Tom [Stoppard] and I went to Vienna when it was done there. There was a demonstration. And when we came out for a bow, there was a storm of boos and whistles. I said to Tom, "Gosh it's like a football game. " And Tom said, "Yes, but we're the ball! "

Stearns: Verizon Hall will be transformed into a theater for the occasion, moody lighting and all. Will you visit?

Previn : I have to be in Boston. But I'm anxious to see the new hall.

Mutter: You should come down with me!

Previn : Don't I have a rehearsal in Boston on Monday?

Mutter: You have the day off - in order to pick me up at the airport.

Previn : OK. It's all set. We'll check out the hall, and if you like, you can play your recital there. . . .

Mutter: And if I don't?

Stearns: Some of us in Philadelphia are feeling responsible for your marriage. Although you've given concerts together since the mid-1980s, you extensively toured Europe together with the Curtis orchestra in 1999. Was that a turning point?

Mutter: No comment.

Previn : No comment.

Stearns: May I ask what suggested to you that your relationship was marriage material?

Previn : I didn't want to let her go.

Stearns: Any comment from you, Ms. Mutter?

Previn : Come on! Let's have it. I gave you a good "in. "

Mutter: If you love somebody and want to spend the rest of your life with him, then you get married. Otherwise it would be a beautiful romance. This is a beautiful romance, but it's much more than that.