Regis Philbin is back on "Live With Regis and Kelly" but still not 100 percent, he says, six weeks after his triple heart bypass surgery.

Philbin, 75, returned to his syndicated daytime talk show Thursday. The audience cheered as he walked onto the set with co-host Kelly Ripa.

"Finally back after six weeks. ... Yes, it was six weeks -- and one day," said Philbin, spry and energetic as ever.

But in a press conference, Philbin said he continues to feel post-surgery pain.

"My chest hurts," he told reporters. "People keep telling me, `Hey, you look great.' I don't feel that great but I'm happy to be here."

Why is he back at work?

"Well, because it was time," he said. "It really was. And sometimes you delude yourself into thinking -- you know, you get sort of a wave of hypochondria saying, `Maybe I shouldn't go back, this hurts, that hurts.' Yeah, it hurts but it's not enough to keep me away from the show."

Philbin said he loved having more time with his wife, Joy, but felt pulled back to the "Live" studio -- his "home for many, many years now."

"Frankly, I don't know what I would do without this morning show," he said. "It's a wonderful show. It's exactly what I devised for myself selfishly back in 1961. ... But now it's a part of my life."

David Letterman, host of CBS' "Late Show," was Philbin's first guest on Thursday's program. Philbin was a guest host when Letterman underwent heart bypass surgery in 2000 and recovered from an eye infection in 2003.

While chatting with Ripa, Philbin mentioned he'd lost 8 pounds.

"It is a tough procedure" but the rewards are great, he said of the heart surgery. "But in the meantime, that whole thing is a tough one."