Alonso sampled Toyota's Hilux car in the Kalahari Desert back in March, and will now embark on a much more extensive rally raid training programme with the Gazoo South Africa operation that represents Toyota at the Dakar.

This will be with the aim of having Alonso debut in the legendary rally-raid in 2020, although it's understood the Spaniard retains the option of backing out in case he does not end up feeling sufficiently comfortable or prepared in time for January's event.

"In March this year, we completed a successful two-day evaluation with Fernando in our Dakar-winning Toyota Hilux in Southern Africa, which proved to be a valuable learning experience," Gazoo SA team boss Glyn Hall said.

"Not only did Fernando thoroughly enjoy the experience, but we could see him adapt and improve every time he got behind the wheel. It was clear that Fernando came to the test prepared and was ready to absorb everything we showed him.

"Rally raid is new for Fernando and I’m certain he has the skill and spirit to take on this challenge. As reigning Dakar champions with a long history in rally raid, I’m confident we can work well together with Fernando to build up his confidence for rally raid competition over the next few months."

A four-day test on the coast of Namibia starting on Tuesday will kick off a preparation programme that will take place "in Europe, Africa and the Middle East".

This will include a competitive rally-raid debut for Alonso in the Harrismith 400, the fifth round of the 2019 South African Cross Country Series, scheduled for September 13-14.

Motorsport.com understands that Toyota is planning to have Alonso to contest another two or three races in the lead-up to the Dakar. He is expected to enter the traditional Dakar rehearsal Rally Morocco on October 3-9, as well as the final round of the SACCS in November.

Alonso's foray into rally-raid is the latest step of his campaign to explore various categories of motorsport, which has already yielded two victories in the Le Mans 24 Hours, a FIA World Endurance Championship title and a Rolex 24 triumph.

"I’m really excited to continue my adventure with Toyota Gazoo Racing," Alonso said. "Together we have achieved so much since I first drove a Toyota in November 2017, with our two consecutive wins at Le Mans, the World Endurance Championship for the team and a drivers’ title with my teammates Sebastien [Buemi] and Kazuki [Nakajima].

"I got a taste of off-road rallying earlier this year and it left me with a good feeling that I want to prolong.

"I knew it would be a totally different experience with a steep learning curve but the Hilux just felt great; it gave me so much confidence so quickly and I was improving loop after loop. I’m really looking forward to the next few months of training, getting to know the Hilux and working with the team.

"I’ve always maintained I want to pursue new challenges in different disciplines and I’m at a great team to do that.”

The question of Alonso's co-driver remains open meanwhile, as likely candidate Alex Haro has aligned with another Toyota regular in Giniel de Villiers - who will join Alonso for the upcoming Namibia test days.

Frenchman Jean-Paul Cottret, who has won the Dakar seven times alongside driver Stephane Peterhansel, is seemingly the highest-profile specialist co-driver available.

However, Marc Coma - a five-time Dakar winner in the bike class and the director of the rally between 2015 and 2019 - is instead the likeliest candidate to partner Alonso, although this would require approval from KTM, where he now serves as general manager.

The 2020 Dakar will be held in Saudi Arabia from January 5 to January 17. It will be the first Dakar based outside of South America since 2007, and Toyota will arrive as reigning champion, having clinched its first victory in the marathon with Nasser Al-Attiyah last year.