Marisa Tomei and John C. Reilly's Love Triangle

Marisa Tomei and John C. Reilly talked to co-anchor Harry Smith Friday morning on "The Early Show" about their unconventional on-screen situation.

The two are staring opposite each other in the new upcoming movie "Cyrus." Tomei plays a single mother who has an unusually close relationship with her adult son, played by Jonah Hill. Reilly is a divorced film editor who can't believe his luck with such a lovely lady, until things begin to get uncomfortable.

Jonah Hill On His New Role In "Cyrus"

Smith describes the relationship between Tomei's character and her son as a little bit "Oedipal," and the cast agrees.

"Well, at first he (Cyrus) comes on like, 'Oh, great, kosher, come on in. Would you like a glass of water?' He's so friendly that it's a little strange. At some point in the movie, I realize he's a total psychopath and he's trying to break us up on purpose," said Reilly.

But the relationship between Cyrus and his mother is just a fraction of the movie. The whole screenplay is based around the concept of love, and what each character has to offer when it comes to that.

"(Each character) is up against wanting more love and wanting to expand," said Tomei.

The film is definitely one-of-a-kind. Teetering on the edge between uncomfortable and hilarious, the movie somehow makes its way to an organic level that audiences can relate to.

"Very naturalistic," said Tomei about her experience. "It doesn't feel very -- it doesn't feel very dialogue-y."

The cast said that a large part of the film was done through improvisation, which was possible largely due to the size of the cast and the intimacy of the set.

"That's the cool thing about the movie. It's got big broad laughs that come from having Jonah Hill in the movie and then this really honest, sweet, emotional core," said Reilly.

This intriguing film was written by Mark and Jay Duplass, the same independent movie makers of "The Puffy Chair" and "Baghead."

Even Smith was at a loss when trying to compare the film with another movie.

"Can you think of anything to sort of compare it to? I was sitting there last night saying, I'm not sure I've ever seen anything quite like this," said Smith to Tomei and Reilly.

"It's a comedy that's also a documentary almost, a docu-comedy," said Tomei. "I don't know what you'd call it. It's light and naturalistic that way."

The film will be released in theaters June 18.