Gigi Hadid is more than up for defending herself when it comes to her haters!

The 20-year-old supermodel tweeted a dramatic black-and-white picture of her boyfriend, Zayn Malik, on Wednesday, and it wasn't long before some people started chiming in on their relationship.

WATCH: Gigi Hadid Fights Back Against Body Shamers

Clearly, Gigi didn't appreciate one particular Twitter user -- who has since deleted the remark -- which read, "practice how to walk properly instead of having a new bf every 2 weeks."

"I've dated 3 guys in 3 yrs, hun," Gigi clapped back, referring to her exes Cody Simpson and Joe Jonas, as well as her current ex-boybander beau. "My walk can always get better; I hope the unrelated bitterness in ur heart can too."

... Ouch.

This isn't the first time Gigi has taken to Twitter to defend her relationship with Zayn. Last December, she tweeted -- then deleted -- her thoughts on their budding romance, after some criticized her for dating the former One Direction band member a month after splitting from Joe.

"There's just no need to be judgmental about situations that are not your own. Let live," Gigi tweeted at the time. "Sometimes life just happens. For whatever reason in whatever timing. And sometimes it doesn't make sense til it does. That's it."

"If there was a real way to sit with each one of you and tell you my side of things, I would. But there's not, so I won't," she added. "I've found the only way to happiness is by living as though the microscope isn't there."

Zayn confirmed he was dating Gigi last month. The two are now comfortable showing PDA, judging by this sweet snap Gigi Instagrammed of the "Pillowtalk" singer kissing her on the cheek while she cuddled with her cat, Chub, who unfortunately died recently.

" :( We love you always Chub," Gigi captioned the pic.

WATCH: Yolanda Foster Weighs In on Daughter Gigi's Romance With Zayn Malik

ET caught up with Gigi at the Sports Illustrated Swimsuit Issue party in New York City last month, when she revealed Zayn's thoughts on her super-sexy SI photoshoot.

"He obviously liked the pictures," she smiled.