But they were hiding a pretty huge secret as they arrived at the star-studded Las Vegas ceremony back in May.
For starters, you may remember that the siblings turned up separately. Kylie, 18, posed alone while Kendall was joined by Balmain creative director Olivier Rousteing and fellow model Jourdan Dunn.
Now the latest episode of Keeping Up With The Kardashians has revealed that Kendall and Kylie were actually supposed to walk the red carpet together.
During an emotional conversation, Kylie can be seen telling Kendall that she refused to do any interviews at the event because she was too scared to talk about her father Caitlyn Jenner.
Caitlyn had revealed her gender transition from Kardashian/Jenner patriarch Bruce a month earlier.
Kylie confided in her sister: ‘I totally understand you had your s*** going on. I just felt like I really needed you.’
Kendall replied: ‘I agree with you and I’m sorry and I think next time we will communicate better.
‘I know that you’re really independent, but I think I just have to remember that you’re my little sister and I’ve got to protect you sometimes.’ Aw.
The Billboards fell on the same day that Caitlyn’s About Bruce TV special aired, and Kylie had earlier admitted to her big sister Kim Kardashian that she was nervous about being asked about it.
‘I guess I just still don’t believe that everybody knows. When people ask me about her and talk about it I still feel like we’ve all kept our mouths shut for so long,’ she told Kim.
Kim replied: ‘Obviously everyone’s going to try to ask, but Kendall will be right there with you, so you guys can play off each other.’
But unfortunately for Kylie, Kendall didn’t end up being right there with her.
It wasn’t entirely Kendall’s fault. The 19-year-old had to fulfil commitments for Balmain’s collaboration with H&M.
But before heading out in front of the cameras, Kylie worriedly confessed that she thought she was going to faint at the thought of going it alone.
‘Kendall ditched me. She was supposed to do the interviews with me and I was like: “No, I can’t do it, I’m sorry” and I just walked off,’ Kylie told Kim.
‘I was looking around for Kendall and she wasn’t there. I didn’t know what to say.’
Poor Kylie 🙁 We’re just glad the two got to talk it out and make up.