After splitting with Paul Simon in 1970, he'd seemingly left and gone away. Now he's back.

As Paul Simon’s broadway musical, The Capeman, finally opens on Jan. 29, his erstwhile partner, Art Garfunkel, is entering a new stage himself.

Though he and Simon parted ways 28 years ago, the heavenly-voiced vocalist has had the luxury of following his eccentric muse out of the limelight, thanks to the megaduo’s 1965-70 string of multimillion sellers and some solo hits from the ’70s (”All I Know”). ”I was quite reclusive in the ’80s,” Garfunkel admits. ”I was really at home being an artiste” He coproduced and sang in The Animals’ Christmas, a 1983 orchestral concert of songs by composer Jimmy Webb — in which Garfunkel invested four years and $1 million of his own money — and in 1989, he published Still Water, a book of poetry. He read the dictionary back to front. He perfected his foul shot (he sank 102 straight buckets on a Manhattan playground). And, in 1984, the egghead singer with a master’s in math started walking across America. Really. After 40 expeditions of as many as 100 miles each, Garfunkel completed the Walk in September 1996.

But he didn’t stop moving forward. In 1997, he (1) toured Europe to promote his 1996 album Across America; (2) released a Grammy-nominated kids’ record, Songs From a Parent to a Child; (3) performed for President Clinton; and (4) voiced the singing Moose for the PBS animated series Arthur. And in James Brooks’ new film, As Good as It Gets, Garfunkel — who read for the role that later went to Greg Kinnear — lends his sweet tenor to the closing reprise of ”Always Look on the Bright Side of Life.”

The new year will probably see Garfunkel starting on a new solo album — and his life story. ”I said I was too young to do an autobiography,” says the 56-year-old singer, ”but my agent says it’s a new business now.” And 17 years after Garfunkel reunited with Simon for their 1981 Central Park concert and tour, they’re back together again — on CD. Their boxed set Old Friends has drawn good reviews — except from Simon himself, who griped in The New York Times Magazine that ”there’s nothing of any value in it.” Garfunkel disagrees. ”It represents a body of work I’m really proud of,” he says emphatically.

Off stage, too, everything is feelin’ groovy. In 1988, Garfunkel married for the second time; he and singer-actress Kim Cermak, 30, have a son, James, 7. ”Having a child, you realize you can’t be fanatically anything,” he says. ”It’s very nice — you become this other kind of person.” For Garfunkel, it seems, life is as good as it can get.