The two retailers are stocking the t-shirts that aim to raise money for the sport-focused charity, which is an offshoot of Comic Relief.
David and Victoria Beckham and their three sons have designed the range that feature "The Beckhams for Sport Relief" logo.
Sainsbury's is also sponsoring a multi-distance fundraising run in which supporters will complete either one, three or five miles to raise money for the charity.
The Sport Relief Weekend runs from 19 to 21 March, with entertainment and sports events taking place across the country.
Celebrities including Lawrence Dallaglio and Jenson Button will take part in sports challenges during the weekend.
Sport Relief launched in 2002 and more than 1.25 million people have taken part, helping to raise over £75m.
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