Liar Liar (1997)

Conniving attorney Fletcher Reede is an ace in the courtroom, but his dishonesty and devotion to work ruin his relationships. His wife, Audrey, has left him for a more dependable man, and Fletcher often breaks the commitments he makes to his beloved son, Max. When Max wishes his dad would stop lying for 24 hours, Fletcher suddenly finds that he can only speak the truth, on the day his career-deciding court case has to be won.