Paris Hilton Says 'It's Been Really Nice' Spending Time with Kim Kardashian Again

Robyn Merrett

After publicly falling out years ago, Paris Hilton and Kim Kardashian are now in a really good place.

“I’ve known her my whole life and we’ve been having so much fun together lately,” Hilton, 38, tells PEOPLE as she gears up to announce her new position as partner and investor with The Glam App.

“I’ve known her my whole life and we’ve been having so much fun together lately,” Hilton, 38, tells PEOPLE of her friendship with the Keeping Up with the Kardashians star, 38.

“We had a good time at Kourtney [Kardashian]‘s birthday party and then had fun at Travis [Scott]‘s birthday party. It’s been really nice,” Hilton adds.

Hilton and Kardashian were inseparable in the mid-2000s, posing for paparazzi and hitting the club scene together. Reality TV fans will even remember Kardashian’s first appearances on Hilton’s show The Simple Life, organizing the heiress’ closet and occasionally taking care of Hilton’s chihuahua, Tinkerbell.

But then the pair’s relationship soured and their feud saw the pals exchanging barbs in the media. Clearly, that is now all in the past, and the stars are now not only back to being besties — they are also helping to support each other’s creative endeavors.

Paris Hilton and Kim Kardashian | SplashNews.com

Paris Hilton and Kim Kardashian

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The famous heiress recently paid homage to her reality star bestie in her new song “Best Friend’s Ass,” which was released on May 10.

“All I see is f— boys everywhere trying to make a pass but I can’t stop looking at my best friend’s ass,” Hilton sings on the dance-worthy track.

Hilton tells PEOPLE she wanted the track to be “a summer anthem for girls who rule the night and have fun. Not caring about boys and all about your best friend.”

Kim Kardashian and Paris Hilton

“When you listen to the lyrics it’s hilarious. I sent the song to Kim and she loved it,” Hilton says. “With a title like that, I, of course, had to have her in it.”

Hilton posted a series of Instagrams to promote the song, including two with Kardashian, who will make an appearance in the upcoming music video.

RELATED: Paris Hilton Thinks Kim Kardashian Becoming a Lawyer Is ‘Really Brave’

“It’s these two girls who are going in the club and as soon as they put on these Instagram Goggles they go into an alternate universe and it’s this perfect world,” Hilton says of the video.

“We went to Nightingale. It’s just a really fun night. Just basically showing reality versus the fake social media world. It looks like the most amazing party.”

In addition to focusing on her friendship with Kardashian and her successful music career, Hilton is venturing into the tech industry with her role with The Glam App —  a beauty on-demand service that delivers beauty experts (makeup artist, nail technicians and hair stylists) to your front door.

The Glam App 

Hilton is working alongside the company’s founder Joey Maalouf and CEO Katrina Barton to expand brand partnerships and innovative marketing campaigns.

“It’s like the Uber of beauty services,” Hilton tells PEOPLE. “It’s so much more convenient than having to go to a salon. You’re not wasting your whole day.”

“The tech space is something I’ve always had a passion for. I’m a huge undercover nerd. I love beauty as well. After using the app for the past four years, we started talking about me being involved. I wanted to be the face of the brand and take it to the next level.”

Paris Hilton | Gregg DeGuire/WireImage

Since joining the team, Hilton says she’s “changed the entire site.”

“I’ve added a new ‘VVIP’ experience, which basically gives users access to my makeup artist, who I’ve worked with over the years.”

“People will basically have the option to work with a celebrity stylist. It also has a bunch of cool new features plus new limited edition looks from Joey Maalouf — ‘Paris’ and ‘Hollywood.'”

Much like her career interests, Hilton’s wardrobe has evolved over the years.

“I still love to dress up and have fun at night when I’m DJ-ing or performing. But, in my everyday life and going to business meetings [my style] is a lot more elegant — not as glittery. I’m really into suits now.”

However, the heiress says her style is still “original,” adding that she’s “the OG.”