Joining the agency are Liz Whiston and Dave Shelton - the pair behind HHCL & Partners' "fourth emergency service" campaign for the AA - and Richard Baynham and Ian Gabaldoni from Saatchi & Saatchi, who are best known for their NSPCC and Army campaigns.
The third team is Robert Spicer and Adam Griffin from Bell's former agency Leo Burnett. Their most prominent work was for Heinz Salad Cream and McDonald's.
Bell said: "These hirings are evidence of my determination to bring the best and nicest creative people into JWT. Liz and Dave and Richard and Ian will direct creative projects as well as writing their own work. Rob and Adam have only been in the business for four years but they are creative directors of the future."
Whiston, a writer, and Shelton, an art director, launched their advertising careers in 1987 at Horner Collis & Hirvan before moving to HHCL, where they worked on the AA, Mercury and produced Ronseal's "It does exactly what it says on the tin."
In 1995, they set up HHCL Brasserie and over the next six years created commercials for McCain pizza, The Disney Channel and Martini. When the agency closed in 2001, the duo separated before recently teaming up as freelancers.
Baynham, a copywriter, and art director Gabaldoni started out at Grey London before joining Saatchi & Saatchi in 1994. During a decade at the agency, they were promoted to the board and scooped two D&AD silver Pencils.
Finally, the move reunites Griffin and Spicer with Bell, whom they worked under at while at Burnett.