Cathay Pacific Airways and British Airways will launch a codeshare agreement on flights between the UK and Australia on 31 March.
The deal covers BA's twice daily London Heathrow-Hong Kong service, plus Cathay Pacific's onwards flights to Sydney, Melbourne, Adelaide, Perth, Brisbane and Cairns.
BA will maintain its pre-existing direct service from Heathrow to Sydney via Singapore.
The British flag carrier's partnership with Cathay Pacific follows the cessation of a codeshare deal with Australia's Qantas on the so-called kangaroo route.
Effective 31 March, Qantas will instead team up with Emirates Airline to use Dubai as a bridging point for traffic between Australia and Europe.