Christina's pre-baby body was on display in a sexy black bikini during the funny footage.
"I had to reshare this video (taken almost a year and a half ago) after all the messages I have received about 'scissor paper stone' actually being called 'rock paper scissors,'" Ant, 40, wrote as the caption while he and Christina, 36, played the classic hand game.
Ant playfully called Christina "rude" on Instagram recently after she put his "stinky" work boots outside.
There will be more funny moments for the married couple very soon as Christina is about to give birth to their first child!
The mother-of-two is having a scheduled C-section on Friday, September 6. She went into detail over her decision to do this on Instagram on Thursday, August 29.
Baby number one for Christina and Ant will be a boy. She has two children, son Brayden and daughter Taylor, with ex-husband Tarek El Moussa.