Back in the early 1990s, Jeff Daniels’ agents thought his decision to do “Dumb and Dumber” was — what’s the word? Dumb.

“The night before I flew out to LA to start the wardrobe fitting, three agents got on the phone and said, ‘We’re gonna stop this. You’re not gonna do this movie,’ ” Daniels tells The Post. “I said, ‘No, I want to do comedy, and I need to change it up.’ ”

The movie ended up being a massive hit, and it transformed Daniels’ image from serious dramatic actor to someone who could also do comedy.

On Friday, Daniels and co-star Jim Carrey are back in “Dumb and Dumber To.” The sequel picks up 20 years from when the original film left off, with nitwits Harry (Daniels) and Lloyd (Carrey) setting off cross-country to find the now-grown daughter (Rachel Melvin) Harry never knew he had.

Getting back into Harry’s idiotic shoes for the second time was much easier than the first.

“He’s so dumb, he can’t just be quirky or flawed,” Daniels says. “You had to go to a depth of dumbness I hadn’t done before. An actor finds a key thought, then does the movie through that key thought. Mine was, ‘He has an IQ of eight.’ Not seven, not nine, but eight.”

Here, Daniels shows just how low his IQ can go, answering five dumb questions.

1. You attended Central Michigan University. Dumbest class?

I took a karate class. One day, we were in our white robes with our white belts, and a guy did a flip on me and threw me down. I held onto him and threw him down, too. I got pissed. So now we’re not doing karate at all, we’re just wrestling, and the teacher is going, ‘All right! Bow to each other.’ Yeah, right. So I dropped the class and went and took bowling.

2. Dumber haircut: Lloyd or Harry?

Oh, Lloyd. Absolutely. On the first movie, I saw Jim had done a salad bowl thing. We were in a Holiday Inn in Provo, Utah, and I just got the shampoo, which is probably not the highest quality. I threw away the conditioner and the brush. Every day, I’d shampoo with that cheap shampoo, towel dry and walk out the door. Never touched a comb for eight weeks.

3. Since “Dumb and Dumber” was released, have you discovered a more annoying sound than that one Jim Carrey makes?

Usually it’s when I turn on C-Span and watch Congress.

4. You live in Michigan. Does your agent think that’s dumb?

No. They were very supportive of the move back in 1986. I wanted to raise my kids in a place I could understand. As long as I was willing to get on a plane at my own expense, they didn’t care. There was really only one time I had to get on a plane and go out to LA and audition, and that was in the early 1990s. I auditioned for four movies and one was “Dumb and Dumber.”

5. Dumbest thing your character does in this movie?

Licking Lloyd’s fingers [after Lloyd has shoved them down the back of his pants]. I made one request of myself as I drove to Georgia to shoot this movie. I said, ‘You have to be fearless.’ When you’re with Jim and the Farrellys, there’s an outrageousness, and you just have to dive in. Licking the fingers? It didn’t matter. Jim could have put them where the sun don’t shine, and I still would have gone method and licked them.