Emirates Skywards and Heathrow Rewards have teamed up to allow members to reciprocally earn and redeem miles/points.
The move affects the 14 million members of the two loyalty programmes.
It allows Emirates Skywards members to convert Skywards Miles into Heathrow Rewards, and for Heathrow Rewards members to do the reverse.
Skywards Miles can be put towards Emirates flights, upgrades and other rewards with the airline's partners.
Heathrow Rewards points can be spent at hundreds of shops at Heathrow, redeemed for airport shopping vouchers or used for discounts on pre-booked parking and Heathrow Express train tickets.
Each conversion is instant both ways and is therefore carried out in real-time.
Thierry Antinori, Emirates' executive vice president and CCO, said: "New partnerships like Heathrow Rewards complement our already extensive product offering. As the UK's hub airport, where we operate five daily A380 flights, this partnership makes perfect sense for us and for our loyal Emirates Skywards members."
It emerged last week that Emirates is putting the final touches to a new luxury bedroom product which will exceed the standards of its existing first class cabins (see news, May 5).