St-Pierre, 32, discussed the drama leading up to his UFC 167 welterweight title fight against Johny Hendricks, along with a range of other notable topics.
The Canadian is one of the most recognizable stars in the sport, and he now has a lucrative Under Armour endorsement deal under his belt.
"GSP is one of the biggest MMA stars in the fastest growing sport in the world and his dedication to training and making himself the best at what he does perfectly aligns with our Brand’s mission” states Under Armour Vice President, Steve Battista.
St. Pierre became the first fighter signed by Gatorade in their March 2008 Campaign, and he now has Under Armour behind him.
St. Pierre will become the face of Under Armour’s popular BoxerJock and BoxerBrief Underwear line that is due to be released this Spring.
Additionally, there will be a campaign with St-Pierre for the ColdGear apparel line and the Recharge post-workout suit for this upcoming holiday season.
St-Pierre, the long-reigning 170-pound French-Canadian star, is scheduled to fight Hendricks on Nov. 16, 2013 at the MGM Grand Garden Arena in Las Vegas, Nev.
"He's a superstar, and he was a superstar when we met him," said Mike Fonseca of Creative Artists Agency (CAA), which has represented St-Pierre for four years. "We just had to take him and figure out how we were going to market him."