Louis Tomlinson has been criticised for allegedly promoting a weight loss website on Twitter.

The One Direction member has been branded 'irresponsible' after linking his 13.9 million followers, many of whom are impressionable young teenagers, to a web page selling slimming products.

The 21-year-old star's faux-pas began yesterday morning when he hailed a smoothie drink from British company Bootea, writing: 'Had an amazing @BooteaUK smoothie from Bootea.com this morning #booteashake.'

However, Louis quickly deleted the offending tweet after fans discovered the website predominantly sells 'intense' weight loss and appetite suppressing diet supplements, including a supposed fat-burning tea.

Charity director Lucy Russell - whose YoungMinds organisation helps young people improve their mental health - told the Daily Mirror: '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.' '

A spokesman for One D said: '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.'