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David Letterman's mother Dorothy Mengering, a Midwestern homemaker who became an unlikely celebrity in her 70s as she baked mystery pies and covered the Olympics for her son's late-night show, has died. She was 95.

Letterman's publicist Tom Keaney confirmed Mengering's death Tuesday for The Associated Press.

Letterman had been on the air for years, and had made ironic celebrities out of dozens of nobodies, before he thought to bring on his mom.

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But the moment he did, she became a hit, with a cheerful "Hi, David!" in her Indiana accent starting every appearance.

David Letterman, right, the host of "The Late Show with David Letterman" on CBS, and his mother Dorothy Mengering share a laugh during the dedication of the $21 million David Letterman Communication and Media Building on the campus in Muncie, Indiana on Sept. 7, 2007. Michael Conroy / AP, file

The two had great on-air chemistry, her homespun sincerity proving the perfect foil for her son's urban acerbity.

Her first appearances came via satellite from her Carmel, Indiana, kitchen for a segment called "Guess Mom's Pies," which became a Thanksgiving tradition. Letterman would make a huge production of the bit before finally declaring, usually correctly, "chocolate chiffon!" or "rhubarb!" When he was wrong, she would take on a comforting tone like he was a boy who had lost a little-league game.

She soon started making annual Mother's Day appearances too.

She really became a star when the show took her out of the kitchen.

PHOTOS: David Letterman's Celebrated Broadcast Career

Mengering was a correspondent for the Letterman's Late Show on CBS at the 1994 Winter Olympics in Lillehammer Norway, a role she reprised for the next two winter games, wearing bulky snow gear that made her tiny self almost invisible, and oozing pure sincerity even in absurd bits Letterman's writers had her perform.

"After Lillehammer, I couldn't believe how it all took off," Mengering told The New York Times in 1996. "I think it's about the idea of mom and of a family."

Mengering lived all her life in Indiana. She married Letterman's father, a florist named Harry Letterman, in 1942. He died in 1973, and she married structural engineer Hans P. Mengering, who died in 2013.

Once famous, she put out a cookbook, 1996's "Home Cookin' With Dave's Mom," that included recipes such as "Dave's Fried Baloney Sandwich" and the secrets behind many of the pies she had baked for the show.