Nurmagomedov is in Australia on a promotional tour, telling fans how he become one of the biggest names in sport during a live Q&A session at Olympic Park.
Williams posted photos of himself and Nurmagomedov on Twitter and Instagram, one of them where he was on stage with the reigning UFC lightweight champion.
"Alhamdulillah. Blessed to meet & share the stage with the brother @khabib_nurmagomedov May the most high continue to bless your journey," Williams wrote.
The 33-year-old is a big fan of the Russian star, having posted numerous tweets about the Russian.
Nurmagomedov hasn't fought inside the Octagon since he beat Irish sensation Conor McGregor at UFC 229 in October, which turned into chaos as a violent brawl broke out after the bout.
Williams is currently going through pre-season preparations with the Blues ahead of the 2019 Super Rugby season.