Reigning WEC LMP2 champion Sam Bird will replace Toni Vilander in Ferrari's 2016 factory line-up in the GTE Pro class of the series.
Bird, who dovetails WEC duties with a Formula E campaign for DS Virgin, will join Davide Rigon in the one of the Italian manufacturer's two all-new Ferrari 488 GTE machines.
He was previously expected to land the reserve driver role for Toyota's LMP1 team after a test in Bahrain.
The Briton has prior experience with Ferrari in WEC, having recorded an LMGTE AM podium with AF Corse behind the wheel of a 458 Italia in the 2014 season opener at Silverstone.
Rigon's former squadmate in the #71 car - James Calado - will move over to the #51 machine to partner Gianmaria Bruni.
Calado has so far scored 10 WEC podiums but is still chasing a maiden win, while Bruni won the GTE Pro title in 2012, 2013 and 2014 before finishing runner-up last year.
Vilander, who partnered Bruni in the 2014 title-winning campaign, has been switched over to the IMSA series, running an 488 GTE alongside former F1 driver Giancarlo Fisichella.