Although before quitting BBH the duo had been in touch with TBWA's chairman and creative director, Trevor Beattie, the deal taking them to TBWA was only finalised in the past seven days. Copywriter Pickering and art director Dawson will both take creative partner roles in the agency next month.
Beattie said Dawson and Pickering's role would combine writing ads with overseeing the look of the work in the department.
"Getting these great names is an inspiration to the young teams and that's why they'll have a dual role. Essentially, they'll guide the look of the department's work, he said.
Beattie and Pickering both worked in the creative department at BMP 15 years ago, prior to the latter teaming up with Dawson. Beattie had approached Pickering and Dawson before their move to BBH in June 2001.
"We've always been admirers of TBWA and think there's a great creative atmosphere there, Dawson said.
The duo become the second high-profile former BMP team to join the TBWA creative department in the past 12 months, following the return of Ed Morris and James Sinclair last July.