hang on to your hat
Also, hold your hat. An expression warning someone of a big surprise. For example, Hang on to your hat, we're about to go public, or Hold your hat—we just won the lottery. This expression may allude, according to lexicographer Eric Partridge, to a wild ride on a rollercoaster. [Colloquial; first half of 1900s]
Words nearby hang on to your hat
hang in the balance,
hang it,
hang loose,
hang on,
hang on someone's words,
hang on to your hat,
hang one on,
hang one's head,
hang out,
hang out one's shingle,
hang out to dry