Jehan Daruvala tested for McLaren last month at Silverstone and will undertake another two days of testing with the papaya squad on Monday and Tuesday at Portimao.
It's unclear why McLaren has granted the Indian racer several outings onboard its 2021 MCL35M as the 23-year-old is supported by Red Bull.
But the tests are perhaps part of a personal programme set up by Daruvala.
McLaren's test team has been on site at Portimao since last week where it ran IndyCar star Colton Herta and sim driver Will Stevens.
"My first taste of Formula 1 machinery was surreal and I can’t wait to get back in the car again in Portimao," commented Daruvala.
"I came away from the Silverstone test with a lot of confidence as both from a driving and physical perspective I did well and covered more than two race distances absolutely trouble-free.
"My dream has always been to race in Formula 1 and this test will build on what we achieved at Silverstone."
A three-time winner in the FIA Formula 2 Championship in which he has raced since 2020, Daruvala currently sits fourth in the series standings with Prema Racing.
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