Jack Robinson, before you can say

there is nothing wrong with this phrase, but be aware of how many such expressions are male-based. Balance their use with female-based expressions, creative expressions of your own, or sex-neutral alternatives: in two shakes of a lamb's tail, on the double, in a jiffy, immediately if not sooner, before you can say "knife," right off the bat, in one fell swoop, in a pig's whisker, pronto, straightaway, lickety-split, in the same breath, in the wink/twinkling of an eye, at the drop of a hat, in double-quick time, on the spot, at once, immediately. See also sex-linked expressions.