Back in 2011, the GOAT of BJJ Roger Gracie trained with then UFC champion Georges St Pierre Gi and No Gi.
Roger was quoted as saying about the experience to Graciemag:
Training with him is great. We trained gi and no-gi. On the ground the weight difference is a bit awkward. We did some cool punch, kick, and take down training, and he’s a specialist in that. He gave me some key pointers that will help a lot in my fight, finer details that changed my game.
GSP is a legit BJJ black belt under Bruno Fernandes.
In an interview with TATAME, Fernandes talked about GSP’s Jiu-Jitsu:
“In the UFC, Georges shows only a small part of what he knows. As his main objective is performance, the focus is on what is efficient. In training, he is very versatile, and has a complete game standing up and on the ground. I’ve been training with him for years and he always aims to improve his Jiu-Jitsu, “
“Without a doubt, he is a legitimate BJJ black belt. He’s already a black belt for over 9 years and it took him quite a while to get there. Well before being famous he has practiced Jiu-Jitsu, including going to New York to train at Renzo Gracie academy with John Danaher and others. With or without kimono I’m sure he’d do against very well against other competitors on the current circuit.”
Here is their No Gi roll:
And their Gi roll: