New Zealander Hartley was at one time last season's man in reserve - after a brief stint with former stalwart David Coulthard in the hotseat while Hartley's FIA Super Licence was approved at the beginning of the season - but latterly had to cede the role due to commitments in both the F3 Euroseries and Formula Renault 3.5. However, this season, the 20-year-old is back in the big time with another reserve drive after impressing in a November test for STR. He will, however, continue to drive in other formulae.

"My goal remains the same as every year," insists Hartley. "Take as many wins as possible, and the title as well."

For Ricciardo (below), the long-held dream of every aspiring racer - a seat in F1 - is also closer to reality, with the 21-year-old Australian also due to occupy a reserve role. Ricciardo finished last year with a flourish, winning the British F3 title at the first attempt with seven wins and earning himself the November test session in the Red Bull RB5 F1 car that the team's principal Christian Horner had promised him. Ricciardo will also contest the Formula Renault 3.5 series in 2010.

Hartley and Ricciardo will have equal billing and attend alternate races in their reserve role.

The full driver line-up across both the Red Bull Racing and Scuderia Toro Rosso teams is now complete. RBR were the first team in the paddock to announce their line-up, retaining last year's winning combination of Sebastian Vettel and Mark Webber. STR also confirmed their intention to maintain the status quo with the announcement last week that Jaime Alguersuari would get another chance to impress alongside Sébastien Buemi.

Keep up with the all the news of the teams' build-up to the 2010 opener in Bahrain at www.redbullracing.com and www.tororosso.com