The headliners for UFC Fight Night 126 were Donald "Cowboy" Cerrone and Yancy Medeiros. But their thunder was stolen by one of the celebrities sitting ringside. 

At one point in the evening's festivities, the camera panned to Nate Diaz, UFC contender and winner of The Ultimate Fighter 5. Diaz gestured to the camera - and then pulled out what appears to be a blunt. Check it out below.

This is nothing new for Diaz. In August 2016, Diaz vaped openly at a post-match press conference following a gruelling match with Conor MacGregor. “This is [a vape pen], it’s CBD," explained Diaz at the time. "It helps with the healing process and inflammation and stuff like that. So you want to get these for before, after the fight, training. It'll make your life a better place.” 

He's not the only person in the UFC who thinks so. Comedian and UFC commentator Joe Rogan said this on the podcast Bloody Elbow in 2015:

"A tremendous amount of UFC fighters smoke pot...I mean, a massive amount where it's a huge issue with them involving drug tests, you know, where they have to stop smoking weed for the last four weeks or so in order to pass drug tests. More UFC fighters smoke pot than don't smoke pot."

It seems like people are listening. Shortly after Diaz's press conference vape, the USADA (United States Anti-Doping Agency) changed one of their rules. Effective January of 2018, CBD is no longer on the list of banned substances.

h/t CBS Sports