The "Hero" singer made her announcement during a pre-recorded interview with Ellen DeGeneres for a segment due to air later today, Thursday, Jan. 15 on The Ellen DeGeneres Show.
"I'm going to do my first-ever residency in Vegas at Caesars," a smiling Carey announced. "This is a special event for me. And again, I have to hope that the fans will enjoy this because I’m gonna be performing, which was kind of inspired by my album Number 1’s, and this is now the updated version with 18 of them," she explained.
"Hopefully other people will enjoy this," she added, as DeGeneres marveled at her having had 18 number one hits. "I’ve never done this before. Some of these songs I’m like 'Really, I’m gonna do this again, okay?'" she said, laughing.
Carey is thought to have finalized the deal last week when she was spotted in Las Vegas, having a meal at The Cheesecake Factory in Caesars Palace with her 3-year-old twins Monroe and Moroccan.
She joins fellow singer Britney Spears in the high rollers' vacation spot, who has been in residence at Planet Hollywood Resort & Casino for over a year.
In August 2014, Celine Dion postponed her residency at Caesars Palace indefinitely to care for her husband Rene Angelil (who had a tumor removed from his throat in December 2013) and focus on her children.
Watch the video above to see how Carey broke the news to some of her fans in Vegas over the weekend (wearing a French maid's outfit, naturally!).