Or maybe Colbert is just stirring the pot once again in the ratings war with Jimmy Fallon by showing him just how easy it is to read/give the signs.
Now of course we're being flippant, as both Kidman and Colbert are married and have met before, so we mostly think this is just two people enjoying each other's company and sense of humor. The two are former co-stars after all.
Kidman was on 'The Late Show' to promote 'The Killing of a Sacred Deer' but actually spent most of her time reminiscing about her Emmy and Oscar wins, drinking shandy and not remembering her time on the set of the 'Bewitched' film reboot. But you can't blame her for blocking that one out.