With 100 days to go to London 2012, triple Olympic champion Usain Bolt wants to "amaze" the world by running 9.4 seconds for the 100m and 19 seconds for the 200m.
Jamaican Bolt, 25, is the reigning Olympic champion and world-record holder over both distances, with times of 9.58secs and 19.19secs.
Bolt's 9.58secs 100m World Record was set at the 2009 World Championships in Berlin.
Meanwhile American swimmer Michael Phelps, a 14-time Olympic champion, said he hoped London would be the perfect ending to a stellar career.
England footballer David Beckham, who hopes to be part of the GB side, expressed his pride at the possibility of competing in his home town.