An ad for Britvic's J2O drinks brand posted by Made In Chelsea star Millie Mackintosh on her Instagram account has been banned for failing to inform viewers that it was a commercial endorsement.

The video post seen on June 12 showed an image of Mackintosh and concluded with a scene that included the text: "J2O spritz #BlendRecommends" and continued "More of my #BlendRecommends with @drinkj2o Spritz to come! #sp."

A viewer complained that the post was not obviously identifiable as an ad.

Britvic said the ad was one of a series posted by Mackintosh as part of a commercial endorsement.

The company said the ad was identifiable as a marketing communication, highlighting that the end frame was branded and included the product name as well as the campaign hashtag #BlendRecommends.

It also ensured that the hashtag "sp" - short for sponsored post - would be included to make it as clear as possible to consumers that they were ads.

The Advertising Standards Authority (ASA) said consumers would not be aware before viewing the post that it was an ad.

It said: "We considered the ad was not obviously identifiable as such and therefore concluded that it breached the code."

It ruled that the ad must not appear again in its current form, adding: "We told Britvic to ensure their future ads were obviously identifiable as such and they made their commercial intent clear prior to engagement."