The former prez addressed his supporters at a rally in Pennsylvania Monday, where he took a moment to take shots at late-night TV. Specifically, Trump appeared to take an issue with Jimmy Fallon and his version of 'The Tonight Show,' which he described as "dying."

During this tangent in his address, the Republican nominee called on Carson to return to the long-running talk show and asked the crowd ... "Where's Johnny Carson???"

Trump appeared to double down on his call, adding ... "Bring back Johnny!!!"

Trump has seemingly forgotten that Carson died back in January 2005 after a years-long battle with emphysema. Not to mention, Carson had been retired from late-night television for 13 years at the time of his death ... having handed over the reins to Jay Leno in 1992.

Perhaps Trump was just feeling nostalgic for a different time when he wasn't the butt of every monologue joke -- Hosts Fallon, Jimmy Kimmel, Stephen Colbert, and Seth Meyers have all roasted 45 at one point or another over the years ... with some being harsher than others.

Though, we're surprised Trump is so upset with Fallon ... who faced an immense amount of backlash for having DT on the show back in 2016 -- and infamously mussing his hair.

Perhaps Trump wasn't a fan of the "Saturday Night Live" alum's apology ... where he expressed regret over the awkward interview.