The Olympic stars will appear on the first episode of the new series on Saturday (August 18) to discuss their London 2012 success.
Fellow Olympic champion Jessica Ennis was previously announced as a guest on the show. The gold medallist joins Colin Farrell, Kelly Brook and musical guest Rita Ora.
"Jessica is the woman of the moment. To have her confirmed for the show's comeback next Saturday night is fantastic," a source said.
"Despite her huge success, she is very down-to-earth and humble. Viewers will lover her."
Daley and Bolt were recently named the world's most popular Olympians on social media, coming in first and second place respectively.
Daley won bronze in the men's 10m platform at the London Games, while Bolt won gold in the men's 100m, 200m and 4 x 100m relay finals.
Photo gallery - London 2012 Olympics best bits:
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