AMV beat fellow roster agency St Luke's in a final shootout to hold the account.
Fallon had also been involved in the pitch, but withdrew in June at the same time as it resigned from the BT roster, citing creative differences.
The move is a major shift in strategy for BT, which previously had used AMV to only create campaigns promoting single strands for the different services it offers, including fixed line, broadband and digital network services.
The campaign, set to launch in November, will link the different parts of BT's consumer businesses. The campaign aims to make sure that viewers are able to instantly recognise campaigns coming from BT, whether it is an individual ad talking about landline charges of 5.5p an hour or finding the best BT Broadband package.
Tim Evans, group marketing and brand director at BT, said: "We want to make a clean break from the approach we've had in the past, putting out different campaigns for each service.
"With AMV we will be launching a single, integrated campaign across all areas, so our advertising will reflect the increasingly converged world of communications we now live in."
St Luke's continues to work on BT's digital and 118 500 services. Previously, Fallon had worked on advertising for BT's narrowband and phonebooks accounts.
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