The pair have worked together since 1996 when they joined TBWA. Both work across copywriting and art direction.
In 1998, they crossed over to JWT and won awards for their work for Nik Naks, Smirnoff and Sudafed. While at JWT, the pair also worked on campaigns for Nestle, Persil, J&B, Jaguar and Vodafone.
Since 2006, Pennings and Clarke have been freelance, and have spent time at Rainey Kelly Campbell Roalfe/Y&R, Krow, DDB and Lowe.
At DDB, the pair won gold at the 2007 Campaign Poster Awards for their Financial Times "carrot and stick" work, which also appeared in that year's D&AD book.
In January, they joined Ogilvy Advertising on a freelance basis, to work on brands including Ford, Pilsner Urquell and Comfort.
Will Awdry, the Ogilvy Advertising creative partner, said: "Not only are Steve and Serge highly accomplished, they're also extraordinarily energetic, hurling themselves at brief after brief with engaging enthusiasm."