Fernando Alonso will drive an F1 car again in Bahrain

Fernando Alonso tests Toyota's Dakar rally car (1:43)

Fernando Alonso gets behind the wheel of the Toyota Hilux for the first time in South Africa. (1:43)

SAKHIR, Bahrain -- Just four months after turning his back on Formula One, Fernando Alonso will return to the wheel of a contemporary McLaren F1 car on Tuesday as he takes part in a tyre test with the team in Bahrain.

Alonso announced his decision to leave F1 at the end of 2018 after saying he wanted to pursue other goals, such as victory at the Indy 500 with a McLaren-entered car. He treated last year's Abu Dhabi Grand Prix as his final race -- complete with a leaving party in the paddock and a one-off livery on his car -- but refused to rule out a comeback under the right circumstances.

Although Tuesday's test, which will involve driving to a run plan dictated by tyre supplier Pirelli, does not constitute a full comeback, it will see him get a taste of the car he turned down for 2019. He will complete a full day at the wheel of the MCL34 on Tuesday before sharing the second day of the test on Wednesday with current McLaren driver Carlos Sainz.

In an interview with ESPN last year, Alonso gave the following reasons for walking away from F1.

"I explained it very clearly in my statement: I am stopping Formula One because there are other bigger challenges outside Formula One than the ones I can see here. It's not because I am not winning here, I could sign for a competitive team next year, maybe not the top two, but maybe the third one. But I say no because I arrived in F1 17 years ago and I have won two world championships.

"I have won more races than what I dreamed of when I came here and this part of my career is done -- it was a success. I have ticked the box. I need to go for another tick and find another box to fill. That's the only reason." During pre-season testing in February, McLaren announced Alonso as an ambassador and test driver, confirming that he would be in the car at some point this year.

McLaren will run two cars at the test, with Alonso's dedicated to tyre testing, while a second is used for the team's own test programme. That car will be driven by Sainz and Lando Norris on Tuesday before Norris has the car to himself on Wednesday.

F1's tight testing regulations mean that at least two of this year's four in-season test days must be completed by a driver with less than three races' experience. But tyre testing, which all teams take part in at some point during the year to help Pirelli develop next season's tyres, falls outside those regulations.

Because Norris will have competed in only two races by next week's test, he will still count as a young driver, allowing Sainz to drive at least one and half days at the next in-season test in Barcelona.