Kendall Jenner Reveals Which of Her Sisters Is the 'Worst' Mom

Kendall Jenner not only reunited with her ex Harry Styles, but she also confessed which one of her sisters she things is the "worst" mom. The two came together for James Corden's Spill Your Guts or Fill Your Guts where both Jenner and Styles had to confess to a few hard-hitting truths. How the game works is if the celebrity chooses to answer the question, they don't have to eat what's in front of them — which is usually pretty gross — but if they don't answer, then they have to eat the odd food item. The first question the super model was asked was out of all of her siblings, which one does she find to be the worst parent. She confessed that her oldest sister Kourtney Kardashian is who she finds to be the "worst," although she mentions that they're all great parents.

"You are one of the few members of the Kardashian, Jenner clan that does not have children. Rank your siblings, Kim, Kylie, Khloé, Kourtney and Rob from best to worst parents," Styles asks as Jenner and the audience start laughing.

Jenner responded with, "I feel like I could answer it," as she laughed holding 1,000-year-old egg nog. Styles chimed in and said, "I feel like I could answer it."

"I'll start by saying they actually are all amazing, they really are" Jenner continued. Styles then said, "Okay," as he looked to the crowd while they laughed.

Jenner then began to answer the question, saying, "I'd say Rob is number one — he's so good to his daughter. And then, I mean that's so hard they're all amazing!"

Styles then joking encouraged the model to just drink the eggnog since it sounded like she didn't want to answer the question.

"Then it would be, like, Khloé, Kim, Kylie, Kourtney," she finished as she burst into laughter.

Jenner and Styles dated in in 2013 but it only lasted for three months. However, they've rang in a few new years together and each time they've looked super cute. On New Years Day in in 2014, the two were spotted skiing together in Mammoth, California.

"Kendall snowboarded and Harry skied," a source told PEOPLE. "They were very cute together. There was a lot of flirting and smiling going on. Harry was a gentleman and even offered to carry Kendall's snowboard to the ski lift."

Two years later, they were spotted again vacationing in Anguilla in the Eastern Caribbean. Another source revealed that the two "acted like a couple" and looked "very cozy and happy" together.

They've continued to see each other at random outings on-and-off throughout the years, so fans were very excited to see them on TV together as they filled in for the host. Only time will tell if they'll ever start dating again.