Hilo's BJ Penn will defend his UFC lightweight world championship against Boston's Kenny Florian in Philadelphia on Aug. 8.

The main event for the UFC 101 card was officially announced by the UFC yesterday. Penn said several weeks ago that his next bout would be against Florian.

"BJ Penn is called the Prodigy for a reason," UFC president Dana White said. "He has proven to be dangerous in multiple weight classes, but he is definitely at his best at 155 (pounds)."

It will be Penn's first bout since he lost to Georges St-Pierre for the UFC welterweight (170 pounds) championship in January.

Penn, who has a professional record of 13-5-1, has not lost in the 155-pound division since 2002. He is 7-0-1 in his last eight lightweight bouts.

Florian is 11-3, and became the No. 1 contender in the lightweight division by reeling off six consecutive victories.

"Originally known for his outstanding jiu-jitsu skills, Florian is now as well known for his devastating Muay Thai," White said. "Both of these guys excel standing and on the ground, so I am expecting non-stop action in this world title fight."

In a co-main event at UFC 101, Brazil's Anderson Silva will take on Georgia's Forrest Griffin in a non-title bout. Silva is the UFC middleweight (185 pounds) champ, but the bout against Griffin will be in the 205-pound division. Griffin is a former 205-pound champ.

Two other Hawai'i fighters will appear on the UFC 101 card.

Maui's Kendall Grove will take on Ricardo Almeida of New York in a middleweight bout; Hilo's Shane Nelson will face Aaron Riley of Washington in a lightweight bout.

The UFC 101 card will take place at the Wachovia Center. Ticket prices range from $50 to $600, and are available through http://www.ufc.com.