Lesson of the day: don't mess with Gigi Hadid!

The usually cheerful model turned serious when she called out a fan on Twitter Wednesday after the user insulted her runway walk and love life.

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The 20-year-old had shared a photo of current boyfriend Zayn Malik when a follower commented, "practise (sic) how to walk properly instead of having a new bf every 2 weeks."

Despite her over one million fans, the blonde beauty noticed the comment and wrote back, "I've dated 3 guys in 3 yrs, hun. My walk can always get better; I hope the unrelated bitterness in ur heart can too."

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Talk about a clap back!

The mean tweet has since been deleted, but fans of the runway star have come to her defense with words of encouragement.

For those keeping track, before her relationship with the One Direction singer, Gigi dated singers Joe Jonas and Cody Simpson.