that'll be the day

Idiom1,028/1,085

used when you are saying that sth is very unlikely to happen

Heard in 3 movies · American Movie
Pay for the film, get the three grand back, pay everyone back, take profits-- That'll be the day.
Idioms · 1,028 of 1,085
    that'll be the day meaning & examples · 3 movie clips · from American Movie (1999)