A local artist, Nathan Wyburn, created a portrait of the singer in pizza sauce.
"Who's hungry???? Thanks @nathanwyburnart for my pizza portrait! #cardiff," Groban captioned his shot.
Added Wyburn on his Instagram page, "Ah so this just happened! "OMG man I saw your tweet, your work's awesome! It's an honour to be included in your collection!" - Josh Groban! @joshgroban #cardiff ???????? #FoodArt #pizza #PizzaArt #joshgroban #notthatkindofart #painting #drawing @motorpointarenacardiff"
Wyburn, who is 25, according to his website, is famous for his unique take on portraiture.