Ted Turner, the founder of CNN, is being treated by medical experts as he recovers from a bout of pneumonia that landed him in the hospital ... TMZ has learned.

A rep for Turner tells TMZ ... the legendary media mogul has been recovering at a rehabilitation center in Florida following a recent hospitalization. The rep tells us he'd suffered a "mild case of pneumonia."

The rep says Ted "expects a full recovery."

This update comes more than 6 years after the media mogul revealed -- during an interview with Ted Koppel on "CBS Sunday Morning" -- he'd been diagnosed with Lewy Body Dementia.

At the time, Ted described a variety of symptoms he was struggling with ... including exhaustion and forgetfulness.

For those unfamiliar with LBD, the progressive brain disease is the 2nd most common type of dementia -- the first being Alzheimer's disease. In fact, in his 2018 interview, Ted expressed gratitude for not receiving an Alzheimer's diagnosis ... noting LBD was "not nearly as bad."

Ted -- who famously married his third wife, actress Jane Fonda, in 1991 before she divorced him in 2001 -- is best known for pioneering the first-ever 24-hour cable news channel. The noted philanthropist also founded the TNT and TBS cable networks.

The rep for Ted tells us he remains "resilient and engaged in professional and personal endeavors."