AceShowbiz - Rob McElhenney is being likened to Sloth from "The Goonies" after sharing a post of an extreme "allergic reaction" he appeared to have suffered to his face.

The "It's Always Sunny in Philadelphia" star, 46, who became a co-owner of Welsh football team Wrexham AFC with actor Ryan Reynolds, 47, in November 2020, shared a photo of his shockingly swollen face - which he said was caused by eating nuts - as part of a photo dump on Instagram showing images of his highlights of 2023.

"Aside from that slight allergic reaction to the nuts, 2023 was one of the best years of my life. Thank you to the people and places that made it possible. My life is full of love and joy because of you. (Red heart emoji). So excited for 2024. I'll stay away from the nuts," he said alongside the carousel of images, which opened with the one showing his severe allergic reaction.

Despite appearing real, fans of "It's Always Sunny in Philadelphia" pointed out it was make-up used for an episode in season 16 of the show in which Rob's character Mac was stricken by a nut allergy reaction.

Rob's snap was taken behind-the-scenes of the show's making, but many of his 1.7 million followers on Instagram mistook the reaction as genuine.

One commented, "I can't tell if that's legit or makeup!" while another fan said, "Rob, this made me almost drop my phone. My son screamed!" Others quoted deformed giant Sloth's "catchphrase" from "The Goonies" and filled Rob's comments feed with the line, "Heeey you guuuys!"

At the start of the "Philadelphia" episode where Rob's character suffered an allergic reaction, his lips started to swell and became rounder in size. Towards the end, the right side of Mac's face was totally unrecognisable and swollen.

Rob's other highlights snaps from 2023 showed him with "Deadpool" actor Ryan and him meeting Prince Harry.