ET spoke with Smith at the premiere of the new comedy on Monday night, where he gushed about getting the chance to direct Affleck again and some takeaways from the reunion.
"Dream come true, honestly," he raved when asked about Affleck agreeing to appear in the sequel. "It's all post-heart attack. I had a heart attack, like, a hear and a half ago, so I honestly feel like, most of the time I was shooting the movie I felt like, 'Oh, I died and this is all heaven, wish-fulfillment stuff. Working with him again dialed my clock back. Made me feel like a kid. Took me back to the mid-to-late nineties."
In the new film, set several years after the events of Jay and Silent Bob Strike Back, the titular heroes (played by Jason Mewes and Smith) find out that the original Bluntman and Chronic film -- a superhero movie based on them -- is getting remade in the form of a modernized, gritty reboot. So, they head back to Hollywood to somehow stop the production. Affleck's role is a cameo, but according to Smith, it's pretty demanding.
"He's incredibly prepared. …He had an eight-page scene and one-page monologue that was all his, nobody helping, and nailed it," the 49-year-old director shared of the A-lister on the red carpet. "He could have done the monologue in reverse. His memorization is incredible."
In July, ET also spoke with Smith at Comic-Con in San Diego, where he offered some more insight on Affleck's role and revealed that the film was already in production when he reached out to the leading man, meaning the writer-director had to scramble to make sure he gave Affleck the right part.
"I had a good sleep on it, and I woke up and I was like -- Ben played Holden, who was the co-creator of Bluntman and Chronic in the mythology of our movies and stuff, so I could pull him into the third act," he recalled at the time. "Basically, there's a scene that is the emotional culmination of the flick, that's his scene, that didn't exist prior. It was, like, one throwaway visual moment. But with him going like, 'I'll come out and play Holden,' we were able to do an eight-page sequel to Chasing Amy, right in the middle of Jay and Silent Bob Reboot."
"And he gave us, like, it's one of the best scenes -- if not the best scene -- in the movie," he added of the surprisingly heartfelt moment. "It's incredibly emotional, it's some of his best performance, definitely some of my best writing. And it's in a Jay and Silent Bob movie! That, to me, is the trick, that to me is like -- after 25 years in this business, I've gotten to a place where I can take the least likely vehicle and put stuff in it to deliver to your heart that you might be surprised by."
Along with Affleck, the movie also features cameos from Rosario Dawson, Chris Hemsworth, Tommy Chong and more.
Jay and Silent Bob Reboot arrives in theaters on Wednesday.