King, 23, will be expected to feature among the frontrunners in the F2 class of 2017, having finished 12th and seventh respectively in his two campaigns in the series so far.

But the Briton, who has switched from Racing Engineering to MP Motorsport, says returning for a third year in the now-renamed series was already a "difficult decision".

And while several past champions have done four or more years in the series, King has all but confirmed he will be moving on at the end of the year.

"[MP] have really come with a deal that was very hard to refuse," King told Motorsport.com prior to the news of GP2's rebranding.

"I've had numerous deals from teams up and down the grid to stay in GP2, and it was never going to be an easy decision - one, to either stay in GP2, and two, for what team to go to.

"It was always a difficult decision to do GP2 again this year. I did have numerous deals elsewhere in motorsport - but this was a deal that I found it hard to say no to.

"And that's why I only made the announcement in mid-February, because it did take three months to decide whether it was the one I wanted to do.

"As for a fourth year, I suppose that probably answers the question anyway, that a fourth year would be too much and I'd be looking to move elsewhere in my motorsport career."

Asked what motorsport categories would interest him for 2018 if there wasn't a viable path to a Formula 1 race seat, King said: "How long's a piece of string?

"There are numerous racing categories around the world - you've got Super Formula, you've got IndyCar, you've got the World Endurance Championship, then the national championships of sportscars, there's loads of things.

"And the motorsport industry doesn't just stop as a racing driver, it extends a lot further. You see lots of racing drivers, like Christian Horner, for example, who's moved on to being a team principal and has done very well at it.

"You see a lot of other racing drivers turning into driver coaches or actually going to some of the filming world and help people to learn how to drive for doing films. I remember one of my teammates, Ollie Millroy, he's actually turned into a stunt driver and seems to do quite well out of it.

"But for me the goal has always been Formula 1 world champion, and I want to be racing at the highest level I can. So if it wouldn't be Formula 1, I suppose the next best thing is something like IndyCar, Super Formula, those sort of high-end performance cars, really."