Red Bull Racing has confirmed that Sébastien Buemi and António Felix da Costa will be the team's test and reserve drivers in 2014.
Buemi raced for Toro Rosso between 2009 and 2011, scoring 29 points, and has been Red Bull's test driver since 2012. Buemi has raced in the World Endurance Championship for Toyota this season, alongside his duties with Red Bull.
With more in-season testing next season, Red Bull has opted to appoint Da Costa alongside Buemi. The Portuguese driver finished in third place in the Formula Renault 3.5 Series in 2013 but was overlooked for the Toro Rosso drive in favour of GP3 champion Daniil Kvyat.
Da Costa, who has been part of Red Bull's young driver programme since mid-2012, has taken part in a couple of young driver tests for Red Bull, as well as numerous appearances in the show car.
"It’s great to be able to announce the signing of Sébastien and António for 2014," said Red Bull team principal Christian Horner.
"Next year sees the biggest change to the Formula One regulations for some time and the return of multiple in-season tests. To therefore be able to call on two such capable drivers is of huge benefit to the team."
"In Sébastien we have a great resource, a driver with extensive grand prix experience and that will be invaluable. António, on the other hand, is an up-and-coming talent with whom we already have a good working relationship. I’m sure that his contribution will be just as important during what is sure to be an intensely busy season."
Da Costa has also been confirmed by BMW as a race driver in DTM.
"It is an honour for me to drive for such a big manufacturer as BMW," he said. "Switching from single-seater racing to touring cars is a new experience, but the cars are great to drive."