Two Snapchat posts by the reality TV star Marnie Simpson have fallen foul of the UK's advertising rules.
The Geordie Shore and Celebrity Big Brother cast member uploaded images of products from two firms that she has business relationships with, without identifying them as adverts.
This was judged to be a breach of the rules against "hidden" advertising on social media.
It is the first case of its kind to have involved Snapchat.
The Advertising Standards Authority (ASA) normally deals with such matters by ordering offending posts to be deleted or amended.
But since Snapchat Story posts automatically self-delete 24 hours after being added, Ms Simpson has not been ordered to take any action.
The two companies involved, however, have agreed to ensure the hashtag #ad appears alongside adverts they produce in the future.
Ms Simpson could not be reached for comment.
The 25-year-old has been a "brand ambassador" for tooth polish-maker Diamond Whites for nearly two years, while her management agency, Unleashed PR, began selling a range of coloured cosmetic contact lenses marketed as being "iSpyEyes by Marnie Simpson" earlier this year.
On 20 June, Ms Simpson uploaded two images.
The first showed her posing with a Diamond Whites case with the text "50% of [sic] everything" superimposed, and a link to the company's site.
The second featured the celebrity wearing a grey lens on one of her eyes, with the words "mrs grey coming soon" placed alongside her.
In both cases an unidentified individual contacted the ASA to complain the images had not been identified as ads.
Diamond Whites tried to defend the promotion featuring its product on the grounds that Ms Simpson's followers would already be aware of her commercial relationship with the firm. But the watchdog did not accept that this would be known by everyone who saw the image.
Unleashed PR suggested that in its case the wording featured was so vague that consumers would not know what product was being advertised or where to buy it. But the ASA said its code still required marketing promotions to be flagged as such.
"These might be our first Snapchat rulings, but the principle behind them is as old as the hills - ads, wherever they appear, must be obviously identifiable as ads," the authority's chief executive Guy Parker told the BBC.
"It's just not fair to expect people to play the detective, to work out the status of a tweet, post or story."