Watch: Kendall Jenner breaks down over dad Bruce's transition

The Kardashians have been nothing but supportive to Bruce Jenner during his transition, but that doesn't mean it hasn't been an emotional rollercoaster for the family. 

A new teaser for Keeping Up With The Kardashians shows the aftermath of Bruce breaking the news to his daughters – and the normally cool, calm and collected Kendall Jenner leaves the room in tears.

Watch the preview, which launched on the Today Show US, above.

The 19-year-old also reflects on her upbringing as a "tomboy" and describes her father as "the most amazing person I know". Nawww, it's nice to see Kendall wear her heart on her sleeve like this.

When Bruce's Diane Sawyer interview aired on April 25, Kendall tweeted: "I love you. So very proud of you, my hero." What a daughter!

The Bruce Jenner KUWTK episode will air in two parts on E! on May 17 and 18 in the US.

Earlier this week, Kendall's mum Kris also turned on the waterworks talking about Bruce: