The singer has lost nearly 50 lbs. since last March
After the “Writing’s on the Wall” singer posted a photo of himself looking noticeably thinner on Wednesday, the Instagram has racked up nearly 3,000 comments.
“OMG @samsmithworld you are too skinny!! Stay healthy!!! pls!” wrote one concerned commenter.
“Doesn’t even look like him like is he going to sound the same,” wrote another.
Even DJ and music producer Calvin Harris weighed in on Twitter, calling Smith’s weight loss “legendary.”
The 23-year-old musician – who lost nearly 50 lbs. since last March with the help of nutritionist Amelia Freer – wore a striped T-shirt for the shot, which appeared to be taken from a balcony.
VIDEO: Sam Smith on His Dramatic Weight Loss: ‘I Went to Bed Dreaming of Tuna Melts’
“California daze,” he wrote.
While a majority of fans found Smith unrecognizable, others praised him for his new look: “You look great. As long as you are healthy and happy with yourself then screw these negative comments,” wrote one user.
Smith has been open about his weight loss in the past.
“It’s not a diet. My relationship with food has just completely changed,” he told Today in September. “I love food so much.”
The basis of Freer’s first book Eat. Nourish. Glow., which kick started Smith’s path to health, is a diet filled with organic vegetables, healthy proteins such as fish and lean meat, herbs and citrus fruits as well as eggs and avocado.
“It’s not about being perfect, it’s not about focusing on your weight, it’s about cooking your food from scratch. Start with one meal a day and build it up,” Freer told PEOPLE. “That, for me, is the foundation of good health.”
A rep for Smith did not respond immediately for comment.