The two actors, who have played the ex-couple Heather and Oz in the comedy franchise, shared that American Reunion still has the same chemistry among the cast as seen in the 1999 film American Pie.
"At the end of American Reunion, there's a lot of photos from the first and second American Pie films in there," Suvari explained to Collider. "When you do look at those, it becomes a reality that it has been that long, but there's so much of this essence that it hasn't been.
"It feels like no time has passed at all. We have so much chemistry with one another that it's so natural. It's the same vibe."
American Reunion, the fourth instalment of the original series, brings back the cast - Jason Biggs, Alyson Hannigan, Klein, Suvari, Tara Reid, Seann William Scott, Thomas Ian Nicholas and Eddie Kaye Thomas - for their high school reunion at East Great Falls.
"We have such a beautiful time, making these movies," Klein said. "The chemistry that you see, as audience members, in these movies is palpable and you can't create that. That is something that either exists in films or doesn't.
"You've watched enough movies where the chemistry isn't there, but in these, it is. We believe in these characters and we can follow these characters. To be a part of something like that, for 13 years now, and to revisit that, it's a really, really cool thing. We're having a lot of fun."
American Reunion opens on April 6 in the US and May 2 in the UK.
Watch the trailer for American Reunion below: