Letterman also put his mother to work as a foreign correspondent of sorts for the show during the Winter Olympics in 1994, 1998 and 2002.
Speaking about the reaction to her Olympic coverage, Dorothytold The New York Times: "After Lillehammer, I couldn't believe how it all took off".
"Well, his dad had a good sense of humor, but I think he may get it from my dad", she said.
A new biography of the television icon, who ended his 22-year run with the Late Show in May 2015, reveals the emotional toll of the blackmail scandal.
One gambit Letterman loved was doing a remote segment from his mother's house on Thanksgiving, during which he would try to guess what kind of pies she had made that year. But that reading would miss the truth of Dorothy's regular player status, which becomes obvious as you look through clips of her appearances: Letterman loved his mom, and thought she was amusing as hell.
Mengering died just a day before Letterman's 70th birthday today. She was seen baking with Hoosier rock star John Mellencamp and touting the prowess of Old Milwaukee beer. Letterman was lucky to have Dave's Mom, and so were we.
Born on July 18, 1921, Dorothy Hofert marred Harry Joseph Letterman, Dave's father, in 1942, and they remained betrothed until his death in 1973. "To me, it's just my mother and this is the way she's been all my life".
Months after the Lillehammer games, Mengering parlayed her newfound fame into a cookbook, "Home Cookin' With Dave's Mom", featuring a guest recipe from Dave for fried bologna. He died in 2013. "But, I was surprised that people took to it", Letterman said.