She said she's finally in a place where she feels comfortable talking about Bruce's transition and what's going on with their family.
"I'm obsessed with my dad," she told ET. "So any time I get to talking about it, especially when it was such a new thing, I would always start crying… But I've kind of gotten to a comfortable space and it's getting to be just a part of my life, and I'm so happy for him."
Bruce Jenner publicly came out as a transgender woman last month in a two-hour interview with Diane Sawyer on 20/20. Kendall said she completely supports her dad.
"I support him in every way," she said. "I think it's something that a lot of people can relate to, and he can change a lot with it and do so much good."
Kendall told ET that the About Bruce special will focus a lot on how the greater Kardashian clan is dealing with the changes. Bruce has said repeatedly that the toughest part of his transition has been telling his kids about it and seeing their reactions.
"I think it will be interesting for everyone to see how we've handled it," Kendall said. "I think that's what everybody wants to see, because no one's really seen that."