Sebastien Buemi will also be Toro Rosso's official reserve driver in 2012.
On Thursday, energy drink Red Bull's main team Red Bull Racing announced that the 23-year-old Swiss "joins Sebastian Vettel and Mark Webber" in the world championship-winning team's lineup this year.
No mention was made of Toro Rosso, Red Bull's Faenza based rookie team for which Buemi has raced since debuting in Formula One in 2009.
But Toro Rosso has clarified that Buemi will also step in should his race successors Jean-Eric Vergne and Daniel Ricciardo be unfit for action at any of the 20 Grands Prix this year.
"Although our sister team in Milton Keynes will be the Swiss driver's top priority, if for any reason, Scuderia Toro Rosso found itself short of a driver at a Grand Prix, then Sebastien would step into the cockpit for us," said the team.