Made In Chelsea star Louise Thompson has apologised after receiving a warning over a post on social media.
The advertising watchdog said it wasn't clear an Instagram story she posted was an advert promoting a beauty brand.
Louise said she was unaware that she should include the word "#ad" to her post to show she had been paid to promote Vanity Planet's product.
She said she would make sure all future posts were labelled correctly.
The story was posted on 3 May and included a video of the star showing a brush product and included a caption promoting Vanity Planet.
It read: "Obsessed with my glowspin! Swipe up for $100 off using my code 'louiseglow'. Swipe up awesome @vanityplanetstore."
The Advertising Standards Authority (ASA) received a complaint that it wasn't obvious the story was an advert.
Vanity Planet said it didn't mean to break advertising rules and the company had since changed its contracts to state influencers needed to meet UK advertising standards.
Louise said she thought her followers would have been aware she was being paid for the post because it included a promotion code.
She apologised for not making it clear and said she would make sure future posts met advertising rules.
The ASA said both Louise Thompson and Vanity Planet were jointly responsible for ensuring that the promotion complied with advertising rules.
The ASA said: "While the post contained some elements that indicated there might be a commercial relationship between Louise Thompson and Vanity Planet, we considered that the content and context of the post did not make clear that it was advertising as opposed to, for example, genuinely independent editorial content or sponsored editorial content."