quicker than you can say Jack Robinson
see before you can say Jack Robinson.
Words That Are Older Than You ThinkThe first citation of "OMG" in the Oxford English Dictionary appears in a 1917 letter from the British admiral John Arbuthnot Fisher to Winston Churchill.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.