Louis Tomlinson
One Direction heartthrob Louis Tomlinson under fire for posting about a weight loss supplement on Twitter. (Reuters) Reuters

One Direction heartthrob Louis Tomlinson has been criticised for posting about a weight loss supplement on Twitter.

The 21-year-old singer tweeted about UK-based health supplement Bootea smoothie, along with a link to the company's website.

"Had an amazing @BooteaUK smoothie from Bootea.com this morning #booteashake," he tweeted.

However, his teenage fans were upset over the post, which has since been deleted. The fans claimed that Bootea makes appetite-suppressing diet supplements.

Sunny: "@Louis_Tomlinson @BooteaUK what happened to TWMYB? This is a dangerous&disappointing message for someone in your position to send to girls"

Elena: "@Louis_Tomlinson @BooteaUK the hell kind of promo is this when a huge part of your fan base are impressionable young teens?! #notimpressed"

lovechords: "@Louis_Tomlinson @BooteaUK can you guys take this down?? R u nuts? You r promoting dieting drinks to teens! whats in ur head?"

Tomlinson's spokesman told the Mirror: "Louis tweeted about the drink as he had one and enjoyed it. However, he did not realise they are associated with weight-loss and would never endorse weight-loss products."

Lucy Russell, the director of campaigns at the YoungMinds charity said: "It's really irresponsible and short-sighted of him. Louis has such a huge audience - especially young girls. It's very silly and remiss of him and the people around him. Three children in every classroom have a diagnosable mental health problem. Louis is a mentor to millions. The ones who are vulnerable are easily led and will be thinking: 'I'll buy some of that.'"