Ryan Reynolds is taking a trip down memory lane. 

On Monday’s episode of the "Today Show," Reynolds, 46, recalled his 2018 experience on South Korea’s adaption of the reality singing competition show, "The Masked Singer."

"When I was there, I was like, 'Why did I sign up to do this? This is horrible! This is truly horrible! I don't know this song. I don't know how to do this,’" he shared. "It was traumatic."

"What's crazy is I was in actual hell," Reynolds continued.

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The actor appeared on "King of Masked Singer," which is what it's known as in South Korea, while he was overseas promoting "Deadpool 2."

"The Adam Project" star was disguised in a unicorn costume, with a sparkly cape as he sang "Tomorrow" from the classic film "Annie."

Ryan Reynolds

Ryan Reynolds admitted that competing on "The Masked Singer" in South Korea in 2018 was "terrible." (Photo by James Devaney/GC Images)

 Host Hoda Kotb brought Reynolds' performance up while he was promoting his upcoming holiday musical, "Spirited."

"Your singing skills have been on display many, many times," Kotb told Reynolds before co-host Savannah Guthrie asked why he was featured on "King of Masked Singer" to begin with.

"I've been doing this job a long time, and you go on these international tours, and you start saying, 'What's the weirdest show we can go on?'" Reynolds shared. 

"And at the time, this was before ‘The Masked Singer’ was in the U.S. So they said, 'They have this show called ‘The Masked Singer’ which is huge in South Korea.' I said, 'We're doing this show. We have to do that show.'"

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He continued: "At the time, no westerner had been on that show before, so it was a big surprise when I lost the mask."

Both the audience and judges in South Korea were in awe when Reynolds removed his mask on the competition show. 

"Hello, everybody. I'm so sorry about that song," Reynolds joked with the crowd at the time.

Ryan Reynolds, Blake Lively Met Gala

Ryan Reynolds revealed he did not tell his wife, Blake Lively, that he would be competing on the show. (Getty Images)

He later admitted he was "absolutely" nervous to compete on the show, and he didn’t tell his wife, Blake Lively, that he would be making an appearance.

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"I was wearing an adult diaper!" Reynolds admitted.

On Monday, Reynolds was joined by his "Spirited" costars Octavia Spencer and Will Ferrell. Ferrell shared that the cast was "thrown into theater camp" to prepare for the musical retelling of Charles Dickens' 1843 "A Christmas Carol."

Will Ferrell

Will Ferrell stars alongside Ryan Reynolds in the holiday musical "Spirited." (Theo Wargo/Getty Images)

"This was seven weeks of rehearsal," Ferrell shared. "Basically, we were thrown into theater camp. Dancing, singing, voice work — the whole thing. It really started with us all staring at each other going, 'Are we ever going to be able to get to the end of this?' And low and behold, we somehow did."

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"Spirited" will be released in select theaters on Nov. 11 before its worldwide debut on Apple TV+ on Nov. 18.