Sinclair is the first hiring by the executive creative director, Malcolm Poynton, since he arrived from Saatchi & Saatchi's Sydney office earlier this month with a brief to revitalise Ogilvy's creative department.
The move signals the end of Sinclair's 11-year partnership with the art director Ed Morris. The news is a blow to Lowe, which signed the duo in January from TBWA/London, where they made the "double life" campaign for Sony PlayStation. Lowe also lost its joint creative director Tony Barry to Clemmow Hornby Inge last month.
"The hiring of James as creative partner is a major coup," Poynton said.
Sinclair said: "My goal was always to work for as many of the best agencies and learn as many approaches to the business as I could. I now have the opportunity to focus that experience on one of the world's greatest automotive brands."