Muay Thai superstars Yodsanklai IWE Fairtex and Rodtang "Iron Man" Jitmuangnon took part in an open workout yesterday.
Both men are set to compete in separate bouts at ONE: A New Era which takes place at the iconic Ryogoku Kokugikan in Tokyo on March 31.
Yodsanklai said: "I am honoured and excited to be part of ONE Championship's first-ever show in Tokyo. More importantly, I have the opportunity to avenge a previous loss to Andy Souwer, and I get to do it in front of the Japanese fans.
"I promise to deliver an exciting performance for everyone there."
Rodtang said: "To be able to compete in ONE Championship means a lot to me, and to be able to compete in their first-ever event in Japan is an absolute honour for me.
"I'm really happy to be in this position. I promise that I won't disappoint the Japanese fans."
Multiple-time Muay Thai world champion Yodsanklai is one of the most popular and accomplished fighters in the world.
Yodsanklai has won close to 200 professional bouts against many fellow Muay Thai legends.
In the process, he captured several prestigious titles, including three Lumpinee Stadium world championships and a WBC world crown.
The lure of testing his skills amongst the world's best strikers in ONE Super Series has drawn him to ONE Championship, and he now finds himself competing on the toughest proving ground of martial arts competition.
Rodtang -- which in Thai means 'tank' -- is one of the most recognisable names in the world of Muay Thai, capturing the Omnoi Stadium world championship on two occasions.
Rodtang has beaten some of Thailand's biggest Muay Thai superstars and will face Hakim Hamech in Tokyo.