The pair, who leave Fallon and Bartle Bogle Hegarty to found the venture, will start the business with Tim Scheibel, the digital creative director at Fallon.
The agency, which is yet to be named, will be an advertising business based around a digital offering.
Mans said: "Our focus is to create business success for brands through creative ideas that become a useful social currency or a welcome injection into today's popular culture. That might mean creating ads as well as applications or products, in joint ventures with clients or as our own intellectual property."
At the moment, the business does not have a backer. Fallon did hold talks with the start-up with a view to taking a share but has since decided not to.
Laurence Green, the Fallon chairman, said: "Mans has made a big difference in a short time. We'll look forward to working with them if the opportunity should ever arise."
Mans and Johan founded Tesch & Tesch in 1996. After six years, during which they won awards for clients such as Saab and Stella Artois and business from Apple and Scandinavian Airlines, the agency was bought by Lowe and became Lowe Tesch. In 2007, it merged with Lowe Brindfors to become Sweden's largest digital agency.
Mans moved to Fallon in September 2008 as its digital strategist while Johan joined BBH as its digital creative director in November 2007.
Scheibel, another Swede, first worked with the brothers in 2001 when he joined Tesch & Tesch. Fallon hired him in March 2009.