Olympic gymnast Beth Tweddle was targeted by "trolls" during a live Sky Sports Q&A session on Tuesday.
One tweet addressed to @SkySportsNews, said: "On a scale of 1/10, how pig ugly would you class yourself?".
Other offensive messages included: "Why did you turn down the role of Lord Voldemort?" and "are all sportswomen lesbians?".
In a statement, quoted by the Guardian, Sky said: "Beth's Q&A was a chance for fans to engage with one of Britain's most successful sports stars.
"We're appalled that some people chose to abuse her. This experience highlights some of the unacceptable and offensive attitudes that can be encountered by women in the public eye".