"Harry Potter" creator and author J.K. Rowling has always been known to speak her mind.
So, when a Twitter user made fun of Wimbledon champ and 21-time grand slam winner Serena Williams over the weekend, Rowling took action.
Read: 'Harry Potter Cursed Child': J.K. Rowling Announces New PlayIt all started when Rowling tweeted "#SerenaSlam! I love her. What an athlete, what a role model, what a woman!" on Saturday.
She also tweeted, "I'm #TeamSerena today, because you don't meet many super-talented people nicer than she is. Go @serenawilliams!"
Someone then made fun of Williams' body, tweeting that she looks like a man, to which Rowling replied, "'she is built like a man'. Yeah, my husband looks just like this in a dress. You're an idiot."