Katie Couric - they switched places.
Jay Leno never had 1 guest host in the history of his show, Katie Couric. She did it for one show. Other than that, usually, he would just air a rerun of a previous show.
Groucho Marx
No. He was never the host, guest host or even a guest on The Tonight Show.
Jay Leno (b. April 28, 1950) is a talk show host. Starting in 1992, he was the host of NBC's The Tonight Show With Jay Leno. In 2009, Leno left The Tonight Show to be replaced by Conan O'Brien. He then launched a new NBC show called The Jay Leno Show. When O'Brien left the network in 2010 due to a timeslot conflict, Leno returned to The Tonight Showwhere he currently is.
jay leno
The Tonight Show hasn't had a guest host since the Johnny Carson years when Jay Leno was the permanent guest host. Katie Couric was a one time guest host when she & Jay Leno switched jobs for a publicity stunt. In 2003, she filled in on The Tonight Show & he filled in on TODAY. There has not been a guest host since then.
Jay Leno replaced Johnny Carson as host of the Tonight Show in 1982, after having been a regular substitute host for Carson.
true.
Billy Crystal
Tonight - 1953 Randall Guest Host 5-12 was released on: USA: 18 September 1956
Tonight - 1953 Cullen Guest Host 4-261 was released on: USA: 24 July 1956
Tonight - 1953 Kovacs Guest Host 5-67 was released on: USA: 4 December 1956