Red Bull Racing have signed Vitantonio Liuzzi and Christian Klien for their first season in Formula One.
Klien raced in 18 Grands Prix for Jaguar in 2004
Both drivers have signed the same one-year contract, but a decision on who will race in the season's opener in Australia has been postponed.
"The team management will decide after tests in January and February who will start alongside David Coulthard in Melbourne," a statement confirmed.
Klein is in pole position to take the seat having driven for Jaguar in 2004.
However, should he fail to impress in the early part of the season Liuzzi has a strong claim to take over the team's second car.
The Italian dominated last season's Formula 3000 Championship and has shown great potential for the step up in class during testing.
Klien had previously told broadcaster ORF the contract did not guarantee him a set number of starts.
The Austrian is currently ineligible to fulfil the Friday test driver role having raced in 18 grands prix last year for the team in its former guise as Jaguar.