The insider divulged that the couples romances have heated up over the last few months, adding, "Especially, Kendall and Bad Bunny."
"When they're in LA, they seemingly haven't slept separately in months," the source said about the duo, who were first linked in February.
The insider then explained Jenner sisters' relationships have strengthened their friendship despite their many differences.
"They're finally at similar places in their lives, and that has brought them closer," the source shared, noting the famous sisters have had group dinners and double dates with their beaus.
"They haven't really been very in sync since they were kids; it's been fun for them to bond over boys. They're constantly texting each other for advice!" the insider added. "Their romances started out as flings but have progressively gotten more and more serious," the source concluded about the foursome.
- Bad Bunny 'Not Interested' in Confirming Kendall Jenner Romance, Insists His Relationship Status Is 'Clear' to Friends and Family
- Kris Jenner 'Flat-Out Asked Bad Bunny When He Was Going to Propose' to Kendall Jenner, Source Claims: Model Made Matriarch 'Promise to Back Off'
- Kendall Jenner Has 'Hinted' to Bad Bunny She’d 'Love to Be Engaged': 'It Feels Right'
As OK! previously reported, while the Call Me By Your Name actor and the Kylie Cosmetics founder have chosen to keep their love out of the spotlight, the supermodel and the rapper have been spotted canoodling all over L.A.
The couple was seen most recently on a casual deli date on Thursday, June 15. The duo has also became known for their coordinated clothing while on their out and about.
On a recent brunch date, Kendall wore blue jeans, a white tank and a brown jacket, while Bad Bunny had on a blue hat, a white hoodie and brown pants. Prior to that, the two went to a Lakers game in matching snakeskin boots.
The loverbirds have been smitten as of late as a source revealed that the reality TV personality has been calling Bad Bunny her boyfriend.
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"[She] was super excited for them to go public," the insider said about the couple who arrived in the same car to the May 1 Met Gala. "They'd been out together before, but this was very much her telling the world that this is her boyfriend."
Kendall "always told her family that when the right guy comes along, they'll know, because she'll parade him to the world," they added.