Kourtney Kardashian and Travis Barker have been painting the town red with their public display of affection (PDA). Now, Kourtney's sister Kim Kardashian is sharing her thoughts on her sister's whirlwind romance.

Kim appeared on Thursday’s episode of “The Ellen DeGeneres Show.” During her appearance, the “SKIMS” founder was asked whether Barker might appear on her family’s upcoming Hulu project.

The 40-year-old reality star said "I honestly haven't talked to him about it, but I'm assuming since he's such a big part of Kourtney's life that hopefully, they will be on."

Talking further about her sister's romance with Barker, she said "I love their relationship, they've grown so much together. Just to think that they've been neighbors and friends for almost 15 years. Neighbors for like, a decade!"

DeGeneres agreed and soon joked about how the couple haven’t been able to "keep their hands off each other" since going public with their relationship. "They are at each other like it's the last time they're going to see each other, all the time!" the host said.

Kim laughed and commented, “It's a lot, but it's so cute."

"You know what? That's what they do, and it's so cute. And I love love, so I love them," she said.

Recently Kourtney and Barker’s PDA drew criticism from her ex-Scott Disick with whom she shares three kids: sons Mason, Reign and daughter Penelope.

Kourtney’s ex-boyfriend Younes Bendjima recently shared a screenshot of a direct message from Disick that showed a photo of Kourtney and Barker kissing in Italy. "Yo is this chick ok!???? Broooo like what is this," Disick wrote in the message. He added, "In the middle of Italy."

Bendjima responded, "Doesn't matter to me as long as she's happy. P.S. I ain't your bro." The 28-year-old model further shaded Disick in a note he added to the screenshot. "Keep the same energy you had about me publicly, privately," Bendjima wrote.

Though Kourtney did not react publicly to the incident, a source told EOnline that she "doesn't care" what her exes think of her new relationship or "how she lives her life."

According to the source, Kourtney feels that Disick clearly "had a moment of weakness and did something impulsive that he will now regret." Kourtney further said she hopes he will "learn" from this moment.

Kim Kardashian West and Kourtney Kardashian
Kim Kardashian West and Kourtney Kardashian had a memorable night while on vacation in Mexico. The reality stars are pictured attending the premiere of Open Road Films’ “'The Promise” on April 12, 2017 in Hollywood, California. Getty Images