E! News has confirmed the former "Lizzie McGuire" actress is set to play Stacy, a woman who romances Kutcher's character, Walden, right before he falls in love with her grandmother, played by "Taxi" star Marilu Henner.
This will be Duff's TV debut since becoming a mom back in March of 2012.
Duff is best known for her work on TV's "Lizzie McGuire" and "Gossip Girl." Her film credits include "The Lizzie McGuire Movie," "Agent Cody Banks," "Cheaper by the Dozen," "A Cinderella Story" and "Cheaper by the Dozen 2."
The "Two and Half Men" season finale will air May 9 on CBS.