Florence Pugh has urged fans to "think about what you write" as she was forced to debunk rumours about her personal life online.
The Marvel and Midsommar star said she understood how being famous often affected her privacy but fabricated stories about her relationships were "damaging" to all involved.
It comes following speculation that she and fellow actor and friend Will Poulter are dating, following pictures of the two on holiday in Ibiza with other friends.
Writing on her Instagram story, Pugh wrote: "This is getting a little silly now. No, Will Poulter and I are not dating.
"We went to the beach with our friends, who are always about half a metre away from us in every picture, but have been cleverly cut out/ framed out so that it looks otherwise.
She continued: "I understand that the nature of this job is that you sometimes get your privacy completely bulldozed by paparazzi, but to fabricate this stuff actually does more damage than good.
"Thanks for saying we look sexy...doesn't mean we're doing the sexy."
Pugh added: "On another note, an important note....There's no need to drag people through this.
"Regardless of your opinion on who I should or shouldn't be with, at the end of the day if you're complimenting someone by trolling another person.. you're just bullying.
"There's literally no need to be horrible online- no need. Think about what you write. Think about who it affects."
The actress, also known for her roles in Black Widow and Little Women, is due to star alongside Harry Styles in the upcoming film Don't Worry Darling.