The actor and his girlfriend Lauren Miller are engaged, a source confirms to PEOPLE.
"Seth is so excited," the source says. "Lauren is such a sweet girl. She makes him really happy."
Rogen, 28, has starred in a series of hit comedies, including The 40-Year-Old Virgin, Knocked Up, Superbad and Pineapple Express.
Miller, also 28, who lives with Rogen in his Los Angeles home, has had small roles in a few of his films, including Superbad and Zack and Miri Make a Porno.