BJ Penn (born December 13, 1978 in Kailua, Hawaii), is an American professional mixed martial arts fighter and Brazilian Jiu-Jitsu practitioner who is currently the Ultimate Fighting Championship (UFC) Lightweight Champion. In 2000, he became the first American-born winner of the World Jiu-Jitsu Championship in the black-belt category. He became only the second fighter to win UFC titles in two different weight classes (the other being Randy Couture). He is currently ranked by Sherdog and MMAWeekly as the #1 lightweight fighter in the world.