How to implement Google Play Games services using Kotlin

I'm writing a game and I want it to use Google Play Games services for leaderboards, achievements and backing up the user's progress.

All samples and examples online, including Google's own, use Java. I'm writing in, and learning, Kotlin, Google's preferred language for a year or more.

I've searched high and low and cannot find any sites/blogs that help with using Kotlin to implement it, have any of you come across anything that I can use for reference?

Any help greatly appreciated.