First rule of America's Got Talent: Don't mess with Melanie Brown. The former Spice Girl did not appreciate a crude made by Simon Cowell and, boy, did she let him have it.

During Tuesday's quarterfinals, a magician suffered a technical malfunction that resulted in a lackluster performance. While critiquing the act, Cowell compared it to Mel B's wedding night and it did not go over well.

"I kind of imagine this would be like Mel B's wedding night," Cowell said before adding, "A lot of anticipation, not much promise or delivery."

That's when Mel B. channeled her inner Real Housewife and tossed a cup of water in the former American Idol judge's face. As she stormed off the set, host Tyra Banks weighed in on the altercation. "Mel B is out," she noted. "This is live TV, y'all. Live TV!"

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The singer is currently in the process of divorcing estranged husband Stephen Belafonte after 10 years of marriage, so this probably isn't the best time for quips about her personal life.

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However, this isn't the first time Mel B. dumped her drink on Cowell. She previously did it during Week 5 when he made a backhanded compliment saying she deserves more credit for being so successful despite not knowing how to dance. Obviously, he hasn't learned his lesson.

America's Got Talent airs Tuesdays at 8/7c on NBC.