The comedian, 32, started dating the Crazy Rich Asians star in 2011 before they split amicably in 2017. They met on the C4 sitcom Fresh Meat.
However, he revealed in a new episode of Netflix series Travels With My Father that he "could have got married" to the actor if he wanted to.
"I f***ed up my chance of that," he can be seen telling his mother Hilary, adding: "I did."
The episode was filmed before Whitehall began dating his girlfriend Roxy Horner.
The comedian reportedly split from Chan due to their busy schedules.
At a 2018 standup show, though, Whitehall said it was because of their "expectations".
"She wanted kids now whereas I wanted to escape," he said. "I'm not good with kids."
Chan, who appeared in drama series Humans, had a small role in 2019 blockbuster Captain Marvel.
She will join the Marvel Cinematic Universe (MCU) in a larger capacity when 2021 film Eternals arrives. The delayed film also stars Kit Harington and Angelina Jolie.
Watch: Jack Whitehall - Travels with my father