Alonso confirmed last week that he would be competing at Le Mans and the majority of WEC rounds for Toyota this season, alongside his F1 efforts for McLaren.

But with his Woking-based team expected to deliver a good step up the grid following a switch to Renault engines, Webber is keeping his fingers crossed that Alonso doesn’t get too distracted by sportscars and lose out on potential star results in F1.

“He's definitely a racer, and we admire that in him,” said Webber, who is good friends with Alonso. “He wants to race, he wants to race at every opportunity possible. That wasn't available three of four years ago, it just wasn't the done thing.

"Now with less testing in F1, and clearly he's uncompetitive – if he was fighting for a world championship, he'd never be doing any of this.

"He doesn't do much simulator time at McLaren, if any. He's an old-school racer and that's what we all admire about him.

“For him to do Le Mans is great, he's going to really enjoy that. He'll enjoy the whole thing. But I'm not sure what the whole game is. It's fine for him, but I'm not sure how stoked McLaren are with the whole thing.”

He added: “I thought the Indy idea was awesome. Obviously they [McLaren] were really embarrassing last year. Hopefully they'll be a bit more competitive this year.

“I just hope the distractions of trying to bounce around from all the categories, when there's a really good result in F1 on the table, that he doesn't miss it through burning too many candles.”

Alonso praises "rocket ship" Toyota

Alonso tried out the 2018-spec Toyota TS050 Hybrid for the first time last week in a three-day test at Aragon, immediately after contesting the Rolex 24 at Daytona.

The Spaniard said the car’s hybrid boost made it feel like a “rocket ship” – but stressed he would treat Le Mans with the “respect” it deserves in terms of being prepared.

“The car is just amazing, this machine is something very special,” said Alonso. “I think the four-wheel drive, together with the boost of the hybrid system makes the acceleration like a rocket ship.

“You go out of the corners and you feel the compression of the seat and your eyes are very wide open. Any racing driver should feel that, one time.

“I cannot wait until June, but I know that before that big event I need to do some tests, because you need to prepare for that race. You need to respect that race and I will try to do that.”

As well as 21 grands prix this year, Alonso is currently scheduled to compete in four WEC events including Le Mans – but will add another if the Fuji round is moved to avoid a clash with the United States Grand Prix.