Garrison Keillor, "A Prairie Home Companion" host, to retire in 2013

(CBS/AP)  Garrison Keillor, host and creator of public radio's "A Prairie Home Campanion," says his long tenure behind the mic is coming to an end.

The 68-year-old told the AARP Bulletin that he plans to retire in the spring of 2013. But adds he first has to find his replacement.

"I'm pushing forward, and also I'm in denial. It's an interesting time of life," Keillor said. "I sure don't want to make a fool of myself and be singing romantic duets with 25-year-old women when I'm 75. But on the other hand, it's so much fun. And in radio, the lighting is right.

Keillor, told The Associated Press in a follow-up e-mail Wednesday that he'll be 70 in the spring of 2013, "and that seems like a nice round number."

"The reason to retire is to try to avoid embarrassment; you ought to do it before people are dropping big hints. You want to be the first to come up with the idea. You don't want to wait until you trip and fall off the stage," he told the AP.

For the first time this season, "A Prairie Home Companion" had a guest host on Jan. 15, when singer and fiddler Sara Watkins of the band Nickel Creek hosted the show from St. Paul's Fitzgerald Theater with Keillor appearing as a featured guest. Keillor said at the time that he had never gotten to see the show himself and wanted "to stand in the back of the hall and watch for a few minutes."

Keillor has ruminated before about retirement. In 1987, he surprised his fans by quitting "A Prairie Home Companion." But he returned to the airwaves two years later with a new touring show, "American Radio Company of the Air," and a few years after that he returned to St. Paul and reclaimed "A Prairie Home Companion" as the name of his variety show.

In 2009, Keillor suffered a minor stroke but was back on air three weeks later.

Keillor created the show in 1974 in Minnesota. It is now broadcast on nearly 600 public radio stations and heard by more than 4 million people each week.