Jay Dee “B.J.” Penn (born December 13, 1978) is an American professional mixed martial artist and Brazilian Jiu-Jitsu practitioners. Penn debuted and competed in the Ultimate Fighting Championship (UFC), and later in K-1. Prior to fighting for the UFC, he became the first American Gold medalist of the World Jiu-Jitsu Championship. In mixed martial arts, Penn has competed in the Featherweight, Lightweight, Welterweight, and Middleweight divisions. As a former UFC Lightweight Champion and UFC Welterweight Champion, he is the second of only five fighters in UFC history to win titles in multiple weight classes. Penn was also a Co-champion in the UFC 41 Lightweight Tournament, due to an eventual draw opposite Caol Uno in the tournament finale. Through his tenures as champion, Penn unofficially unified the UFC Lightweight Championship (against Sean Sherk) and broke the all-time lightweight title defence record. Penn was inducted into the UFC Hall of Fame, as the inaugural inductee in the Modern-Era Wing by career-long rival Matt Hughes, during International Fight Week in July 2015.