He arrives in L.A. to house-sit for his vacationing brother. Once in town, he falls for his brother's assistant.
The film is directed by Noah Baumbach, the man behind "The Squid and the Whale."
"I like his work. He's interested in human interaction, the minute and details of character," said Stiller. "He's not interested in expected plot twists."
Stiller says that the audience will be able to connect with the characters in the movie.
"I think he's just really looking for something else. He is looking for an emotional connection with people that aren't pandering to the audience. He is trying to show real people and trusting an audience is going to connect with that because they are going to see parts of themselves."
Joining Stiller in the film is newcomer, Greta Gerwig.
"It does feel like a coming out party of sorts. I am very excited. I couldn't imagine a better film, a director, and Ben Stiller" said Gerwig." "I always wanted to be an actress and this is my dream come true."
Gerwig says this is just the beginning and cannot wait to put her acting skills to work.
"I hope to do all different kinds of movies and genres," said Gerwig. "I think it's such an exciting moment when something like 'Greenberg' can be in the theaters along with something like 'Avatar.' I hope I get to be a Na'vi one day."
Maybe James Cameron is watching!