Ferrari principal Stefano Domenicali also told reporters, at a media event in the Dolomites resort of Madonna di Campiglio, that his team will launch their 2013 car at the Maranello factory on February 1.
The first pre-season test starts at the southern Spanish Jerez track on February 5.
De la Rosa, 41, raced last season for the financially-strapped HRT team, absent from this year's starting line-up after failing to find a buyer. He was a McLaren test driver for eight seasons.
The move reunites him with compatriot Fernando Alonso, the double world champion who was runner-up in the championship last year for Ferrari, after they were together at McLaren in 2007 in Alonso's troubled sole season with that team.
"We decided to add De La Rosa to our group of drivers mainly to strengthen one area, namely work in the simulator, which with the current regulations regarding testing, is becoming ever more important," said Domenicali.
Formula One teams cannot test during the 2013 season, apart from a three-day young driver session, which puts a premium on simulator work.
Ferrari also have Spaniard Marc Gene as one of their development driver and De La Rosa's arrival will be seen as further consolidation of Alonso's grip on the team after eclipsing Brazilian team-mate Felipe Massa on the track.
Pat Fry, the Ferrari chassis technical director, was also previously at McLaren.
De la Rosa made his Formula One debut with Arrows in 1999 and raced for Ferrari-powered Sauber in 2010 as well as a one-off appearance in 2011.
"It is amazingly motivating to be working for a team like Ferrari, not just because of what it represents in the history of Formula One and motoring in general, but also because it will be a completely new and very stimulating experience for me," commented De la Rosa on the team website.
"I really hope I can get to work as soon as possible and to help in the development of the car. I am happy to be collaborating with Fernando again and also to be working with Felipe. There's not much time until Australia, but there is a lot to do and I am available to help the team from right now."
The season starts in Australia on March 17.