Tom Hanks will replace Brian Williams on Thursday's edition of "Late Show with David Letterman."  The last minute guest had to be called in when Williams backed out of his scheduled appearance Sunday. 

In some ways, the Hanks encounter should be equally fascinating: Hanks had been at the Rangers game with Williams when the newsman was honoring the veteran, which lead to another accounting of the story that got him into so much hot water in the first place. (At the game, Hanks was also reunited with "Wilson.")  

According to at least one report -- Politico's -- Williams had considered staying with the Letterman appearance even after he removed himself (or was removed) from "Nightly News" for an undetermined period of time. Politico, in fact, called the Letterman appearance "a key part of his recovery strategy."

That indicates that Williams would have probably expected to have been back on "Nightly" by this Thursday, then follow that with an appearance on "Late Show,' which -- had it gone forward -- would have been a late night TV event for the ages.

Instead, more questions. Did Williams back out or did NBC say, "hold on...'  The news division has launched an internal investigation of his reporting. However, it's unclear when the results of the investigation will be known, or whether -- pending results -- NBC and Williams have simply decided  to keep an extremely low profile.

Regardless, the Letterman appearance posed huge risks.  Among many places, it was on this show in 2013 where Williams spun one of the more vivid accounts of his since debunked helicopter RPG story, leading Letterman to even say, "I have re-newed respect for you."

A Thursday encounter would or could hardly have been entirely cordial. But it could also have gone part of the way towards clearing the air, with not only an apology but greater insights into why he told the whopper in the first place.

Williams is a favorite on the late night circuit and has been for years, because he is often very amusing, and -- yup -- a good storyteller.