Platt and Cockerell, who left Alphabet in March, will report to Ian Haworth, the agency's executive director. He is also the head of creative at WWAV.
Since arriving at the agency in January, Haworth has restructured the creative department. The changes have seen the departure of the creative directors Bob Nash and Andy Todd.
Since leaving Alphabet, Platt and Cockerell have been freelancing at Heresy, a sister agency of HHCL & Partners. They are set to join WWAV on 1 July.
Cockerell, a copywriter, and Platt, an art director, have worked together for nine years at agencies including DP&A, Barraclough Hall Woolston Gray, TBWA/ GGT Direct and Saatchi & Saatchi.
Their most awarded work was their "date rape cinema spot for Woman Against Rape, which they did when they were working for TBWA/GGT Direct.
Haworth said: "They are the most dynamic, ideas-driven team I've ever seen. Hiring them is symbolic of the way I see the market moving and will add an edge to our work."
Platt commented: "Ian is trying to get clients closer to the creative product and drive in a different direction to the traditional WWAV way of doing things, so it felt like being round pegs fitting into round holes. It's brave and we want to be part of it."
WWAV has also hired the former Lion creative director John Harvey as a senior art director. The experience he has on fundraising accounts will compensate for the recent loss of the creative director Maria Phillips, known for her expertise in the charity sector.