Carlos Sainz completed his first laps for Ferrari at the team's Italian circuit Fiorano on Wednesday.
Sainz, who joined from McLaren for this season, drove a 2018 F1 Ferrari car at the test. His appearance is part of a week-long test schedule which saw Sainz's teammate Charles Leclerc complete over 100 laps on Tuesday.
Sainz signed his contract early last year for the current campaign, replacing four-time world champion Sebastian Vettel.
The Spaniard was blocked from making an early appearance for Ferrari at the test which followed last year's Abu Dhabi Grand Prix. Vettel was also prevented for testing for his new team, Racing Point, ahead of its rebrand to Aston Martin this year.
Sainz will test throughout Wednesday and will also get to drive on Thursday morning, before handing over to Ferrari academy driver Mick Schumacher, who is making his F1 debut this season with American team Haas.
It is part of Ferrari's preparations for the new F1 season. Pre-season testing takes place in Bahrain between March 12-14, ahead of the opening race of the 2021 season, the Bahrain Grand Prix on March 28.