The NBA superstar will star in "Shaq Vs.," a TV series where the All-Star center will challenge top athletes in their respective sports. During one episode, which debuts on Aug. 8 on ABC, Shaq will swim against Olympic superstar Phelps.

O'Neal, now with the Cleveland Cavaliers, also will try his football skills against Pittsburgh quarterback Ben Roethlisberger, box retired world champion Oscar De La Hoya, trade tennis volleys with Wimbledon champ Serena Williams and play volleyball against Olympic gold medalists Kerri Walsh and Misty May-Treanor.

O'Neal will negotiate a handicap with his opponents and train for one week leading up to each challenge.