IAG, formed by the merger of British Airways and Spain's Iberia, will sign an agreement at this week's Farnborough Airshow to co-operate with Chinese plane maker Comac on the development of its C919 twin-jet.
An IAG spokeswoman said the agreement would enable IAG to have an input on "what customers and airlines want from the new plane".
The company is also expected to consider the C919 as an option when upgrading its fleet in the future.
British Airways signed a similar deal with Comac in 2010. The new deal extends the agreement across IAG.
Comac signed a jet-design agreement with Ryanair last year to help produce a rival to the Boeing 737.