The "Only Getting Better" singer shared a snap from their chance encounter on Instagram on Saturday, April 27, showing her wearing a trademark rainbow bow while Kanye is sweetly wearing his Stormi World T-shirt from his niece Stormi Webster's first birthday party back in February.
"At Tour rehearsals today and Kanye was rehearsing in the stage next to us!" JoJo captioned the photo. "Seriously I've met a lot of people, and Kanye and Kim are literally 2 of the most wonderful people I've ever met! Thank you for being so supportive!".
The 15-year-old sensation recently hung out with Kim Kardashian and Kanye's daughter North West, who appeared in one of JoJo's YouTube videos.
In her video, JoJo spent the day babysitting North, and the pair made glitter slime, danced and played hide-and-seek.
And when Kim picked up her five-year-old daughter from JoJo's house, the youngster exclaimed it was "the best day ever!".
Their unlikely friendship started on Instagram, when the KKW Beauty owner tagged JoJo in a comment about North's hair bow. The former "Dance Moms" star enthusiastically responded, and offered to send Kim's daughter "some special ones".
JoJo has also opened up about working with North on her new YouTube video, and said she was "super excited" to spend time with the budding fashionista.
"North West hasn't really been on the Internet before and no one has really met her personality yet, so it's going to be really, really fun. Kim says she's super excited so I'm excited," she told Entertainment Tonight.
And the teenager even cheekily revealed her relationship with reality star Kim has blossomed.
"Oh yeah, we're best friends," JoJo joked.