What more can be said about Johnny Carson that hasn’t already been said? According to Peter Jones, the PBS documentary producer who pursued the late night host for ten years before being curtly turned down, Carson himself certainly believed all had been aired.

Still, for Tonight Show connoisseurs, the upcoming May 14 “American Masters” series documentary on PBS promises a few new tidbits, most notably Joan Rivers revisiting her disastrous decision to not keep Carson properly in the loop about her discussions with FOX. Ray Richmond, the former Hollywood Reporter staffer now helping with Deadline.com’s TCA coverage, has the details from this morning’s Winter Session panel:

“Joan really speaks about that for the first time with us,” Jones said. “She admits that she probably shouldn’t have let Johnny find out about it second-hand. … Johnny never spoke with Joan again. She called him to discuss it with him and he hung up on her. The whole thing with Joan broke Johnny’s heart, it really did.”

Rivers has managed to tenaciously re-invent herself and was featured in her own acclaimed 2010 documentary. But who knows what might have been if she had not incurred the wrath of Johnny, a topic she has often broached with Howard Stern.

[Photo of Rivers at January 5 TCA Comcast cocktail reception: Joe Seer/Shutterstock.com]