Winning Moves has hidden prize-winning golden cards in packs of London 2012 Top Trumps.
Each card comes with a unique code that can be entered online to claim London 2012 prizes.
Five top-prize winners will get the chance to have a rowing session with Sir Steve himself.
Sir Steve has also been named the official ambassador of the Top Trumps annual schools tournament, where kids compete to become Britians 'Top Trump-er'.
Sir Steve Redgrave said: "I’m delighted to have been appointed the Top Trumps Schools Tournament Ambassador and to be giving school children a fun way to find out more about the Olympic Games both past and present.
"Top Trumps is great fun and a wonderful way to learn a little more about the sportsmen and women who will shape the stories of London 2012."
Left to right: Dan Taylor, Fiona Hortopp, Sir Steve Redgrave, Tom Liddell, Graham Barnes
Fiona Hortopp, head of marketing at Winning Moves said: "We are very honoured that Sir Steve has agreed to partner with us for our Top Trumps Golden Card promotion as well as our Top Trumps Schools Tournament. He is without a doubt the ‘Top Trump’ of British Olympic sport."