Really? Not the swimmer who has the record for most medals? Not the young diver? To name just two. You'd have to be pretty sports and particularly Olympics unaware to have only heard of the very fast sprinter
Anyway, it's none of them I'm thinking of
Someone in their first Olympics but who was already a several-times medallist.
It comes from an Italian publication so its unlikely to be anyone British IMO. The swimmer is not as famous as the sprinter either.