Rolls-Royce said it had won a US$9.2 billion (6.12 billion pounds) order to supply engines for 50 A380 aircraft for Dubai's Emirates airline, providing a boost for the British company after a torrid year of profit warnings.
Rolls-Royce said the order was the largest in its history, pushing its shares up 2.1 per cent to 1001 pence in early trading, making it one of the biggest gainers on the FTSE 100 index.
It is the first time the Gulf carrier has ordered Rolls-Royce engines for its superjumbo fleet, the rest of which is powered by Engine Alliance, a joint venture of General Electric and Pratt & Whitney.
Announcing the deal at a joint press conference in London, attended by Rolls-Royce chief executive John Rishton and Emirates president Tim Clark, the companies said the aircraft in question would enter service from 2016.
The deal was confirmation that of what sources had told Reuters on Thursday.
The contract includes a long-term "Totalcare" package, which means Rolls-Royce will also provide service and maintenance to Emirates for the Trent 900 engines.
Though a shift in engine supplier is rare, the deal will not come as a surprise after Clark said in March he was considering Rolls-Royce engines for the 50 aircraft for which engine selection had yet to be made.
Rolls-Royce is the world's second-largest maker of aircraft engines after US group General Electric, but cancelled orders in other parts of its business, where it makes power systems for use in the oil and gas, marine and industrial sectors have hit its outlook.
It warned in February that profits this year could fall by as much as 13 per cent on top of an 8 per cent drop last year, saying the low oil price had increased uncertainty.