Saudi Arabian Airlines has been identified as the customer for another eight Boeing 777-300ERs, a follow-on order from its deal for 12 signed in 2010.
The eight additional aircraft already featured on Boeing's order books last year, attributed to an undisclosed operator.
Saudi Arabian ordered 12 777-300ERs in April 2010 and revealed the following November that the agreement covered up to 22 of the type.
All 777-300ERs are powered by General Electric GE90 engines.
Saudi Arabian director general Khalid Al-Molhem said the type would "play a significant role" in the carrier's long-term strategy and fleet modernisation.
He added that the new order "reiterates our confidence" in the 777. Last year Boeing secured gross orders for 202 777s, of which 152 were -300ERs. Another 48 were freighters, and the remaining pair were -200LRs.
Boeing values the follow-on Saudi Arabian deal at $2.4 billion, at catalogue prices.