He will appear alongside Jessica Chastain in the twin movies, Myriad Pictures has announced.
The Disappearance of Eleanor Rigby: Hers and The Disappearance of Eleanor Rigby: His explore the life-altering experience of a New York City couple from two different perspectives.
McAvoy will appear as restaurant owner Conor, with Chastain as his wife Eleanor, who has just return to college.
Joel Edgerton was previously attached to the husband role.
Ned Benson (In Defiance of Gravity) has written the scripts and will serve as director on both the films.
"The Disappearance of Eleanor Rigby represents an alternate approach to content," said Myriad CEO Kirk D'Amico.
"New distribution models make it creatively possible for feature films to break out of the format of one 90-minute experience."
McAvoy will next be seen in Filth and Welcome to the Punch.
He is also participating in Robbie Williams's Soccer Aid on May 27.