The Girls Aloud singer said on Twitter that further details of the release would follow shortly.
"Very excited involved with the team GB single for the Olympics!" Walsh said.
"More news coming soon!!! *big smile* "
She then added: "You lot are so lovely! Reading all your supportive messages#thankyou"
Walsh said in February that she has no intention of pursuing a solo music career.
She confirmed last month that as well as reuniting in 2013 for a world tour, Girls Aloud also plan to record new material, possibly a full studio album.
> Cheryl Cole: Louis Walsh made money from Girls Aloud for doing nothing
Watch the Girls Aloud 'Call The Shots' music video below: