The agency won the account in July 2016, succeeding Wieden & Kennedy, which had worked with Ovo for the previous year but not produced any work. Before that, Ovo worked with Fabula, which closed its doors in March.
Brooklyn Brothers founding partner Jackie Stevenson said the agency had enjoyed a "great strategic relationship" with Ovo, and the decision to end the relationship was made "with sadness".
A spokeswoman for Brooklyn Brothers added that the partnership had produced thinking and creative work for Ovo’s pay as you go and pay monthly brands, and that the agency had recently completed a long term strategic development project for the next chapter of the main Ovo brand.
Adam Rostom, managing director at Ovo, said: "We’re hugely proud of the work we’ve developed together and wish the whole team at The Brooklyn Brothers nothing but the best for the future."
Rostom joined Ovo last October as chief marketing officer; he was promoted to MD last month.