In 1957, legendary crooner Johnny Mathis released a single titled "Chances Are," which became his first No. 1 hit. When he performed the song on "The Ed Sullivan Show" that same year, a career was launched that has spanned six decades. During those years, he has amassed a repertoire of close to 1,000 songs.

Yet the key to Mathis' longevity and continued success lies in knowing what his audiences want to hear and giving it to them, as he will Friday at Wolf Trap's Filene Center.

"I have a program that seems to work," Mathis said. "I come on first, and I sing for about a half-hour; songs like 'Chances Are,' 'It's Not for Me to Say,' 'Misty' and so forth. And once I do the songs they are familiar with, it kind of relaxes them. When I come back for the second half of the show, I will continue in that vein and then, all of a sudden, I will sing something they've never heard before. And I get away with it."

Still, with a catalog of hit after hit and his fans screaming for their favorites -- what's a star to do?

Johnny Mathis
» Where: Wolf Trap's Filene Center, 1551 Trap Road, Vienna
» When: 8 p.m. Friday
» Info: $45 in-house, $25 lawn; 877-WOLFTRAP (965-3872);

"I've gone over the years to see some of my favorite performers, and I may be disappointed that I didn't hear certain things, but what I actually came to hear is the embodiment of what they are as opposed to what they choose to sing that night," Mathis said.

In the long run, he has always believed that audiences come to hear his voice and his style of performance. If they get a chance to hear a certain favorite -- which many do -- they are all the more pleased.

Even as he appreciates his ongoing popularity, Mathis doesn't sit still. He is working on a duets album with the talent he has worked with over the years, including Dionne Warwick, Deniece Williams and Barbra Streisand.

"What you do is very much a part of who you are," Mathis continued. "You don't look for success, you look for motivation. It's an ongoing process, [and] I wouldn't know what to do without it."