keep up an act
keep up the act
To maintain a façade or false set of behaviors in order to deceive people. Other words can be used between "up" and "act." The company has kept up the act for so long that I think even they believe their own story at this point. I'm tired of keeping up this act. I just want to tell the world the truth about our relationship! Audiences are left at the end of each episode wondering how much longer the villain can keep up her act before her true colors emerge.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
keep up an actand keep up one's act
Fig. to maintain a false front; to act in a special way that is different from one's natural behavior. Most of the time John kept up an act. He was really not a friendly person. He works hard to keep up his act.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.