"A lot of people say, 'Is it your dream job?' It's impossible for me to dream this," he says in our exclusive first look promo below. "More people have walked on the moon than have hosted The Tonight Show."
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"In my case," he continues, "I've done both, so that's really a corner by myself."
Check out the clip to see Fallon reminisce about watching Johnny Carson growing up and what he thinks Steve Allen would say to him now.
The Tonight Show Starring Jimmy Fallon premieres Monday, Feb. 17.