Jimmy Fallon Pens Heartfelt 'Thank You Notes' for Jay Leno (Video)

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Before taking over as "Tonight Show" host, Fallon offered his gratitude to Leno and pledged, "I will do my best to make you proud every single night."

Before the changing of the guard at NBC, Jimmy Fallon played guest to host Jay Leno on Monday night.

The Late Night With Jimmy Fallon host chatted with the Tonight Show anchor on his final Monday night at the helm, before which Jay introduced him as being there "not to talk but to help me pack!"

After some lighthearted banter about teaching his daughter to read, Fallon thanked his predecessor for all his support -- in his typical comedic fashion, of course. 

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"Are you going to take some of your bits from Late Night to the Tonight Show?" asked Jay. 

"Yes! Whatever works," replied a slightly nervous-looking Jimmy as he clapped his hands. "'Thank You Notes' have been very popular. I actually wrote a few for tonight," he revealed as the band began to play a melancholy tune.

"Thank you, Jay Leno," said Fallon, while writing on a fancy card. "For passing the torch to me. Hopefully it doesn't get intercepted by a Seahawk," he joked, referring to Seattle's blowout win over the Denver Broncos in Sunday's Super Bowl.

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"Thank you, Jay, for teaching me how to be a late-night host -- but was it really necessary for me to 'wax on, wax off' your entire car collection? I didn't know I was going to get Miyagi-ed when I came out here.

"Thank you, Jay, for giving me such great advice for the Tonight Show like you don't need a monologue, and 'Have you ever thought about getting bangs?'

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"And finally, thank you Jay Leno, for carrying on the proud tradition of the Tonight Show host with such humor and class and for being nothing but gracious and generous to me over the past years. I will do my best to make you proud every single night."

The pair shook hands warmly as Leno assured his replacement that he will "do a great job."

Watch the full clip below: