It’s not over until the fat lady sings

Pro Tip 1/3

Originally from opera where a 'fat lady' often signaled the end; now it means things can change.

They were down by 10, but it's not over until the fat lady sings.

Pro Tip 2/3

Make sure people understand it is a humorous expression, not a comment on someone's weight.

I think we'll lose this game—no offense to anyone, you know, it's not over until the fat lady sings.

Pro Tip 3/3

Best used in informal settings, too casual for formal writings or speeches.

We still have a chance to win, remember, it's not over until the fat lady sings.