"I promise to make it up to you," she told fans on Instagram on Wednesday

Credit: Ethan Miller/Getty

Just a week after her triumphant opening night in Las Vegas, Mariah Carey was forced to cancel her show on Wednesday due to illness.

“Hey guys,” she wrote on Instagram. “I’ve been fighting bronchitis for the past few days.. almost better but on mandatory vocal rest per doctor’s orders.

“I’m so sorry to cancel tonight’s show but I promise to make it up to you!!!” she added. “Love you always, MC”

The Grammy winner, 45, who kicked off her Mariah #1 to Infinity residency at Caesars Palace on May 6, has had a busy week.

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The mom of two attended a Chippendale’s show, where her pal Tyson Beckford invited her onstage for a lap dance, and then shot the video for her new song, “Infinity,” which was directed by Brett Ratner.