Ventimiglia was set to portray the daredevil in a limited series on USA that was ultimately scrapped.
"So I love Evel Knievel and it was you, dressed up, it was a screen test for Evel Knievel and you're like, 'I'll send it to you, but don't show it,'" Fallon recalled on Monday before stating that he couldn't remember his phone number and gave the actor his wife's number, thinking it was his.
"I was blonde, I was hairy-chested, I was everything. And yeah, I didn't put anything. I just sent the photo And then I got the 'Who is this?' Ventimiglia said, as Fallon laughed.
Ventimiglia also discussed how he doesn't know what will be happening on his NBC series This Is Us due to the COVID-19 pandemic. The 43-year-old said the pandemic prevents creator Dan Fogelman from discussing what happens in the next batch of episodes with the cast.
"Dan Fogelman, he'll come to set, and this is the difference between, let's say COVID set versus normal filming set. In a COVID set, Fogelman doesn't visit so we don't get that sitting around the campfire, Dan having just walked out of the writer's room saying, 'You guys want to know what happens in the next seven or eight or nine episodes?'" Ventimiglia said.
"So we don't really have that this year, so I'm kind of in the dark," he continued.
Ventimiglia played Emotional Interview with Fallon where the duo were tasked with acting out a randomly selected emotion or situation while having a normal conversation.
Ventimiglia acted as a customer service rep with Fallon as an angry customer and had to act like his tongue was swollen during the game.