Ramsay made the comments during an appearance on The Late Late Show hosted by James Corden.
During the interview, the chef spoke about the latest addition his Bread Street Kitchen restaurant menu, a vegan Sunday Roast.
"Veganism is on the rise, so we’ve got to adapt and we just have to eat a slice of humble pie," he told Corden.
Ramsay has done just that: earlier this year, he launched a vegan menu to celebrate Veganuary, featuring dishes including wild mushroom and truffle risotto and chocolate avocado and almond mousse.
In 2018, the chef added a vegan pizza to his menu, creating media buzz by sharing an image of the cheeseless pizza, tweeting: "Going to give this vegan thing a try. Yes guys, you heard that right."
Morgan had taken to Twitter to say: "Oh FFS, Ramsay... not you as well? This looks utterly revolting."
Ramsay said: "So Piers Morgan is now a food critic?! Go and f*** yourself! Seriously?"