"Interview Donald Trump? I don't know if he would get it," Galifianakis told ET's Sophie Schillaci at the Hollywood premiere of his new movie, Masterminds, on Monday. "He has, like, the mind of an 11-year-old."
The Hangover star says the aspiring politician -- who hosted Saturday Night Live last November -- probably wouldn't get the gag. "I don't really think he would understand what's going on," he explained. "And plus, I would feel like it would um ...we don't have much in common."
Not missing a chance to make a joke, Galifianakis quipped, "I bet his breath stinks."
"By the way, I met him and I know his breath stinks," he added. "So do his sons."
During Monday night's presidential debate, Trump made it a point to call out his longtime feud with Rosie O'Donnell, after Clinton made reference to sexist and misogynistic comments he's reportedly made in the past.
Insisting that he's only made remarks about the former View co-host and no other women, Trump touted, "I think everybody would agree that she deserves it, and nobody feels sorry for her."
O'Donnell, along with several celebrities, responded to Trump's comment, and also shared a clip from The View where she slammed him. "The five [minutes] orange an** can't seem to get over," she tweeted. "Tell the truth -- shame the Donald #ImWithHer."
Galifianakis interviewed President Barack Obama in March 2014, and ET spoke with Between Two Ferns director Scott Aukerman about what it was like having the commander in chief on the show. "We shot [the episode] the way we always shoot them, where it's very experimental and anything can kind of happen," Aukerman explained. "[Obama is a] really funny guy. I mean we've had some really funny people on the show but there's just something magnetic about him when he gets on screen ...He definitely had a lot of slams that he wanted to inflict upon Zach. He was ready. He was locked and loaded."
Aukerman said that the Obama administration was "really hands off" about the interview, and gave the crew the creative freedom they needed to make it a hilarious episode. "They really wanted it to be like a normal episode of Between Two Ferns, which means Zach insulting [Obama] and getting really strange," he noted. "They fully embraced that."