The new company, set to launch in four weeks, will offer strategy consultancy and the implementation of communications solutions.
Simons will be joined by the freelance consultant Bruce Raynor, with whom he has worked on projects for Goldfish and Royal & Sun Alliance.
He is also expecting to sign a head of creativity and a head of planning imminently. The four will become partners in the business.
Passion will work with preferred partners - specialist consultancy firms and communications specialists. This will lower its fixed costs. The company is being privately funded. It has yet to secure any clients, although Simons said it is in advanced talks with potential customers.
Simons said: "It's something that I have always wanted to do for me. It's what I enjoy doing. I'm bored of big, corporate, global stuff. I want to work with entrepreneurial clients."