After realising her error, Carey messaged him: “Wrong Shawn. Sorry. Also I do realise it is NOT Thanksgiving. Haha.”
Mendes, 23, replied: “Hahahaha that’s okay I figured it was an inside joke,” adding two red love hearts.
Sharing details of the blunder on Twitter, Carey added: “My cousin Shawn M and I have this silly joke where we tell each other Happy Thanksgiving on St. Patrick’s Day, @ShawnMendes found out about it today.. sorry Shawn!!”