Kate and Oliver are the daughter and son of actress Goldie Hawn and musician Bill Hudson. The pair also share two half-siblings, Zachary Hudson and Emily Hudson, while Kate also has a half-brother, Wyatt Russell.
Kate and Oliver explore sibling dynamics on their podcast, Sibling Revelry, which they launched in 2019. On The Late Show, the pair said their show celebrates those relationships.
"It started with Oliver and I wanting to do something together," Kate said. "We call it 'revelry' because it's really about how we celebrate that relationship. I don't think people really talk about the importance of it."
"It's a very dynamic relationship, one that is under-explored, I think," Oliver added.
Kate and Oliver recalled how their relationship as siblings got off to a rocky start.
"I think my mom said it started when I came home from the hospital and he was catapulting clementines into my crib, and she had to remove him from my nursery. And it just expanded from there," Kate said.
"I mean, the reality is that we have a very interesting dynamic, and Oliver and I had an interesting upbringing, and no matter how much conflict there was, we were always so close, and then it really kind of hit us when he went to college," she added.
Kate previously said she hopes Sibling Revelry will "inspire people to understand their differences with their siblings and family and always move towards more closeness and connection."