Toro Rosso have named Daniel Ricciardo and Jean-Eric Vergne as their drivers for the 2012 Formula 1 season.
Sebastien Buemi and Jaime Alguersuari make way as the team name an all-new line-up for the first time since their debut in 2006.
Australian Ricciardo, 22, is a Red Bull test and reserve driver and has raced for HRT this year.
French driver Vergne, 21, has tested for Red Bull and took part in practice for Toro Rosso three times this year.
“Toro Rosso's decision to axe both their drivers came as a surprise to some, but perhaps it should not have. The team exists to groom a potential team-mate for Sebastian Vettel at the senior Red Bull outfit once Mark Webber moves on or retires and Red Bull's enthusiasm for Buemi and Alguersuari was known to be well under control. Now they have pitched two more unproven - if promising - talents against each other. Will they fare any better?”
Toro Rosso team principal Franz Tost said: "One has to remember that when Toro Rosso was established in 2005, it was done so with the intention of providing a first step into Formula 1 for the youngsters in the Red Bull junior driver programme.
"It is therefore part of the team's culture to change its driver line-up from time to time in order to achieve this goal."
Ricciardo had been linked to Caterham, formerly named Team Lotus, as a possible replacement for Jarno Trulli, despite the Italian having a contract.
He took part in Friday practice at grand prix weekends for Toro Rosso this year before moving to HRT in the second half of the season, where he drove for the final 11 races without scoring a point.
"This is a really big deal for me," he said. "I have to say that joining Toro Rosso was always my real goal, so a big thank you to Red Bull for giving me this fantastic opportunity.
"To be honest, I am still jumping up and down with excitement at the news. I can't wait to get to work once testing begins."
Vergne added: "I must thank Red Bull for all their support so far and for believing I am ready to take on the ultimate challenge of racing in Formula One.
"Having driven for them a few times this year and also testing for Red Bull, I definitely feel ready to make the move, even if I know there is a big difference between testing and actually racing.
"Sitting on the grid in Melbourne next March cannot come soon enough."
Alguersuari and Buemi finished 14th and 15th this season in the drivers championship, with 26 and 15 points respectively.
Swiss Buemi competed in 55 grands prix over three seasons for Toro Rosso, while Spaniard Alguersuari drove in 46 races.