Jenner and 28-year-old Rocky, formally known as Rakim Mayers, have been sighted in public together multiple times recently, including when they looked cozy at a Coachella party last month.
But up until now, the couple has managed to keep their romance hush hush -- other than being spotted in Paris together a couple of times in 2016.
"Kendall would slip into his concerts, and he's gone to her fashion shows, but they'll usually have secret meetings when he's in the studio," the source told the magazine.
"They also spend time hanging with their mutual friends."
Rocky reportedly gives Jenner a break from cameras and chaos that she often craves.
"Rocky actually keeps Kendall grounded and gives her time away from her crazy family," the source explained. "He is a great escape for her."
Further evidence the supermodel and Rocky are more than just friends surfaced when Kim Kardashian posted a video on Snapchat of herself partying with the pair after the 2017 Met Gala and the rapper grabbed Jenner's butt.
At the time, Jenner's backside was fully exposed when she reportedly rocked a sexy and sheer black La Perla dress.
At the end of the after party, Jenner and Rocky were photographed leaving 1 OAK nightclub together.
Despite the fact all signs point to Jenner having a new boyfriend, Life & Style reported the reality TV star will continue to keep the relationship low-key.
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"They are not in this relationship for publicity, so they won't want a big Kardashian production for the world to see," noted the source.
An insider recently revealed to People that Jenner isn't looking for anything serious with a man yet.
"Kendall's still not exclusive with anyone, but she's definitely been showing more interest in A$AP," the insider said.
"She's just having fun and not taking anything too seriously with anybody right now.