Cobie Smulders has been knocked up with a new role.

The "Avengers" star is bracing herself for an onslaught of sperm jokes as she signs on to join the cast of "Starbuck," according to The Hollywood Reporter.

"Starbuck" follows the adventures of a middle-aged man (Vince Vaughn) whose life is turned upside-down when he discovers that he's fathered 533 children through the noble act of sperm donation. When a handful (only a couple hundred) of these kids express an interest in meeting their biological father, he's torn as to whether he should reveal himself.

Smulders will be playing Vaughn's pregnant (of course!) girlfriend, who knows the legend of the 'Starbuck' but doesn't realize that her beau is the rather virile man behind the myth. Chris Pratt has already been cast in the role of a probably very flustered lawyer.

Cobie Smulders was last seen as S.H.I.E.L.D. Agent Maria Hill in "The Avengers." She recently wrapped Lasse Hallstrom's adaptation of Nicholas Sparks' "Safe Haven," opening Feb. 8, 2013, and will also soon be seen with Paul Rudd, Amy Poehler, Michael Shannon and Ed Helms in David Wain's new comedy, "They Came Together."

Production on "Starbuck" wil commence later this fall under the direction of Ken Scott, who also wrote and directed the original French comedy on which it's based.