The agency replaces LeFevre Communications and Band & Brown Communications, which handled PR for broadband and narrowband PR respectively.
Tony Henderson, BT Openworld head of media relations, said: 'This is a new account. We had separated the work into narrowband and broadband but wanted to look at communications in terms of consumer and business.'
Le Fevre Communications, which still works for BT divisions BT Retail, BT Government and BT SME, is understood to have taken part in the pitch.
This is the first client for Octane, Lewis's newly created consumer tech arm. A 20-strong account team, headed by Lewis V-P of operations Ilona Hitel, is in place.
The team reports to Henderson, Powered strategy and development manager David Frail, BT Openworld business PR manager Kim Fitzsimmons, and BT Openworld consumer PR manager Jasmine Holland.
The hiring of Lewis does not affect iJack, which will continue to work for BT Openworld on online PR.