Former Twitter CEO Dick Costolo is launching his group fitness startup in December

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Costolo left his role as Twitter's CEO in June 2015.

Dick Costolo's next act after leaving Twitter is a group fitness startup called Chorus that's launching in beta this December.

The former Twitter CEO first teased the startup in January, and now a new profile of Costolo in Vanity Fair shares more details about how it will work.

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When it's released this winter, the Chorus app will charge a subscription fee to "link up athletes who share common fitness goals, like training for a marathon, increasing their functional strength, or more ephemeral health resolutions, like sleeping better," according to Vanity Fair.

It sounds like ClassPass, but for people who share common workout routines and health goals.

"This platform will go beyond measurement to motivate and drive improvement and make the road to personal transformation fun and social," Costolo said back in January.

The Chorus website says it's looking for engineers and designers to join its team. Costolo started the company with a personal investment of $8 million at the beginning of the year and is currently raising a Series A funding round that's being led by the VC firm Index Ventures, where he is a partner.

Chorus

The Chorus team.