Dannii is on the judging panel and called on her sister to mentor her contestants, shooting the much-anticipated episode in New York last week.
The songbirds haven't been seen together on TV since 1987 when they were first making a name for themselves on the hit show Young Talent Time.
The sisters spoke to news.com.au and Kylie joked when remembering their '80s TV appearances.
"I don't even want to think of how long ago that was [working on Young Talent Time]. My hair was bigger, my waist was smaller... good times."
Now, she couldn't think of a better person to pair with on the local talent show saying, "Kylie is a huge X-Factor fan."
Even though Kylie is busy recording her latest album, the 45-year-old agreed that it's a perfect on-screen match saying she is "just along for the ride."
"It's really fun to do something together, so it was a done deal when she asked me. This feels normal for us.
"This kind of show is one of Dannii's natural habitats, but I do feel at home on a TV set and being with my sister," Kylie said.
We can't wait to tune in and re-live our favourite pop singing duo!
And you'll see personalized content just for you whenever you click the My Feed .
SheKnows is making some changes!