Mattress Mack is hoping his family's generous contribution toward Mary Lou Retton's medical expenses leads to more donations for the Olympics legend ... telling TMZ Sports it's the least they could do.
Mack -- real name Jim McIngvale -- and his wife, Linda, wrote a check for $50,000 to assist with the gold medalist's hospital bills as she remains in the ICU with a rare form of pneumonia.
We spoke with Mack -- who owns Gallery Furniture in Texas -- about his family's decision to step up in such a big way ... and he said they have been fans since before she became a household name at the 1984 Olympic Games.
"We followed Mary Lou since her career in Houston," Mack said. "My wife and I have always been a huge support of Béla and Márta Károlyi's gymnastics team. My son worked out with them on the team for years, my daughter did as well."
"Mary Lou was always a shining point of light, as George Bush would say, and we pray for Mary Lou's recovery and the $50,000 is the least we could do to help an American icon get better."
In fact, Mack said Linda went through a similar health scare when she suffered a severe lung infection from pneumonia a year ago ... and now that she's doing much better, he hopes the same happens for Mary Lou.
"My parents taught me, and I try to teach my children, and Linda certainly lives that life, that the essence of living is giving," Mack added. "People get in a hard spot, let's help 'em out because one of these days, all of us will be in a hard spot. We're thrilled to help our Mary Lou, we pray for her speedy recovery and, again, I've lived my life by that motto -- 'the essence of living is giving.'"
The fundraiserset up by Mary Lou's daughters has now surpassed its initial goal of $50,000 as she continues to fight for her life... and the donations continue to flood in by the minute.