The joke is on the other foot

Season 36, episode 10, British “Antiques Roadshow”. Valuing some Micky Mouse watches and noting they used to be not worth much, the appraiser said they used to joke, “it’s just a micky mouse watch….but now the joke is on the other foot.” This is a nice mashup of “the joke is on (one)” (a joke or malicious act has backfired) and “the shoe is on the other foot” (roles have been reversed). Both idioms involve a switch or reversal, and both contain the words “is on”. A tip of the hat to Donna Calvert for hearing this one and sending it in!