Katherine Heigl is set to star opposite Seth Rogen in Universal Pictures' "Knocked Up," Judd Apatow's follow-up to "The 40-Year-Old Virgin." Apatow, who wrote the script and is directing, produces with Shauna Robertson and Clayton Townsend.

The story centers on the unexpected pregnancy and other consequences of a man's one-night stand. Heigl steps into the role vacated by Anne Hathaway, who left because of creative reasons.

Paul Rudd and Leslie Mann also have been cast.

Rogen and Evan Goldberg will executive produce.

The movie will begin production next month.

Heigl, repped by Paradigm, is one of the stars of ABC's "Grey's Anatomy." Her feature film credits include "The Ringer" and "Bride of Chucky."

Universal president of production Donna Langley, senior vp production Holly Bario, and creative exec Erik Baiers are overseeing.