Seth Rogen and Rose Byrne ask: Can you be 'Platonic' friends with the opposite sex?

There are existential questions in life: What happens after death? Are there other life forms in the universe? Is there a deity?

And then there’s the burning query posed by “Platonic,” a new Apple TV+ comedy series (first three episodes streaming Wednesday, then weekly): Can adults be friends with someone of the opposite sex?

This is relationship nitroglycerin, folks, so handle it at your own risk. As the show notes, the classic 1989 rom-com "When Harry Met Sally" essentially proved that adding sex to the mix makes things go boom.

“It’s interesting, right?” says Rose Byrne, whose happily married character Sylvia reestablishes a platonic relationship with her recently divorced college buddy Will (Seth Rogen), only to see that friendship creates small explosions in both their lives.

“Can I go away for a weekend, just me and my best male friend?” asks Bryne, 43, who has two sons with actor Bobby Cannavale and also stars as a workout guru in Apple TV+'s "Physical."

"Now, I could go with my girlfriend, simple," she says. "But with a guy? That's a very different dynamic.”

As for Rogen, when asked if he’s had experience with platonic female friendships, he lets loose that classic Rogen snort.

“Every woman I’ve ever encountered falls into that category,” says the actor, 41, who is married to actress Lauren Miller. “Look, friendships are a theme in a lot of my work, starting from ‘Superbad.’ Here, we viewed friendship through a different lens, with two friends who seem to play to their own worst instincts.”

To get this out of the way: Yes, Sylvia and Will stay platonic friends throughout the 10-episode series – by design. "Infidelity is interesting, but it wasn't anything we were interested in exploring in this show," says Rogen.

'Platonic' reminds us that there was something special to our old male-female friendships

Rogen’s comedic chops are rooted in his everyman looks and sarcasm-meets-slightly-baked persona. In “Platonic,” his hipster bar-owning character is just coming out of a tough divorce from a woman whom his pal Sylvia never thought was right for him, which caused their multiyear rift. News of the divorce prompts Sylvia to reconnect.

Sylvia has a life anchored to a motherly routine, and her retro-adventures with Will allow her to discover a lost part of herself.

The roles were no stretch. The comedic duo is very much platonic friends (“Yes, that’s safe to assume,” chortles Rogen) who starred as husband and wife in two “Neighbors” movies (2014 and 2016), directed by Nick Stoller, who co-created "Platonic" with his wife, Francesca Delbanco.

While Rogen’s laugh lines are bold, Byrne’s comedic touches are more subtle. A shoulder shrug here, an eyebrow raise there. The Australian actress, whose breakout role came in 2011's “Bridesmaids,” says she is “a huge Julia Louis-Dreyfus fan; (she's) a genius comedian,” but calls her own approach to comedy more reserved.

“The great comedic actors like Julia and Seth make it look effortless, but I see myself as more of a straight man,” she says.

Delbanco and Stoller, who also directed the relationship comedy “Forgetting Sarah Marshall," first approached Byrne with the idea for "Platonic," who agreed to do the show and asked to re-team with Rogen.

Being just friends means being able to eat cheese-covered French fries like no one's watching

Delbanco says she laments the fact that, societally, her once tight bonds with male friends seem off-limits. “I had guy friends I’d take road trips with, or they’d call late at night just to talk,” she says. “But that’s kind of taboo now, and I miss it.”

In “Platonic,” the characters push boundaries that raise some reality-check eyebrows. For example, Byrne’s Sylvia has no problem hitting the bars until 2 a.m. with Will, and her husband Charlie (Luke Macfarlane) seems to fully understand.

But in other ways, Sylvia is understandably more liberated when she’s with her old college friend. This leads to a hilarious moment in an early episode where Sylvia is at a late-night diner stuffing fries into her mouth in a very guy-like way.

“My wife just loves that scene,” says Rogen, as Byrne nods her thanks. “It’s so funny.” Funny, and slightly nauseating – not unlike the dual feelings that surface when rekindling an old platonic friendship.

“Yes, funny and nauseating, that’s our sweet spot,” he says with a cackle. “That’s what we’re looking for here.”

This article originally appeared on USA TODAY: 'Platonic': Seth Rogen and Rose Byrne channel their real friendship