During his guest appearance on The Late Late ShowWith James Corden on Thursday, TheCrown star revealed some of his favorite drunken memories from the talk show host's September 2012 nuptials to Julia Carey.
As soon as Corden brought up the word "wedding," Smith couldn't help himself from letting out a laugh, slinking in his seat and saying, "Oh, no! Don't mention the wall."
"You were the star of our wedding in many ways," Corden explained. "Do you remember anything about that day?"
That's when Smith didn't hold back, confessing some of the wild shenanigans he got into on Corden's special day.
"I've got a scar on my chin where I fell up the stairs," Smith admitted. "I fell in a fire [place] -- twice! It wasn't alight, thank god; I am a fire hazard."
"I danced with Kylie Minogue, which was glorious," he continued. "And then your dad put me in a car. At the end, he was like, 'Matt... come on, son. It's time. It's time.' He put me in the car; it was a silver Mercedes. I got in and I closed the door, and I got around the side and ran back inside!"
Hear Smith recall the hilarious story below:
ET caught up with Smith on the red carpet at the 75th Annual Golden Globe Awards over the weekend, where he and his co-star, Claire Foy, reacted to rumors about Helena Bonham Carter joining The Crown for the Netflix series' third season. The actress is rumored to be taking on the role of Princess Margaret, Queen Elizabeth II's sister.
"Ahh, that's so exciting," Smith exclaimed, as Foy reminded him Carter is "not official" just yet. "It is the first time I've heard that, officially."
Press play on the video below for more from the exclusive interview!