They have Taco Tuesdays.

With a friendship that spans more than 15 years, Jennifer Lopez and Kim Kardashian West have been through a lot together. Alex Rodriguez, Lopez's fiancé, told People that the relationship between Lopez and Kardashian has changed throughout that time. It started out as a mentorship between Lopez and Kardashian, but as their careers have developed and both have grown in their own professions, they're now bouncing ideas off of each other.

"We've all known each other for a long time," he said. "But Kim and Jennifer are very, very close, and she's almost like a mentee of Jennifer, and Jennifer's mentored her a lot over the years."

The 2019 Met Gala Celebrating Camp: Notes on Fashion - Cocktails
Credit: Kevin Mazur/MG19/Getty Images

"Now, they just go back and forth," he continued. "They mentor each other and they have this really beautiful relationship that goes back over a decade and a half, and it's nice to do anything with Kim and our family."

Kardashian has been open about her admiration of Lopez. Last December, when Lopez came over for a movie night, Kardashian documented it all on Instagram, fangirling and all.

"I'm having a movie night at my house. Never in my life would I have imagined that my idol would want to come have a movie night with me," she said in a Story. "My inspiration for everything has been Jennifer Lopez. I would try and see what shoes she'd wear, what makeup, what hair — I became obsessed with glam because of Jennifer."

Rodriguez said that the Kardashian Wests often join him and Lopez for Taco Tuesdays, movie nights, and holiday gatherings. They even go out for karaoke together, he added, saying that Kim's a great singer.

"We have fun [...] any time we see them," Rodriguez said. "To see how much Kim and Jen like each other, respect each other, support each other is awesome."