Aston Martin has unveiled the car four-time world champion Sebastian Vettel will race in 2021.
Vettel will partner Lance Stroll, son of team owner Lawrence, in Aston Martin's return season this year.
Aston Martin is the rebranded Racing Point team, which was formerly known as Force India. Apart from a handful of grands prix appearances in 1959 and 1960, the British brand has not competed as a manufacturer in F1.
The team has opted for traditional British racing green as the base colour of its livery, while retaining pink accents representing last year's title sponsor BWT.
The AMR21, which is powered by a Mercedes engine, is expected to be a strong midfield contender given the form of Racing Point last year, which included Sergio Perez's victory at the Sakhir Grand Prix.
Under new cost-saving measures for 2021, teams are limited in the changes they can make to their car from last year, but Aston Martin technical director Andy Green confirmed the team has used its allowance, which is controlled by the FIA via a token system, to introduce a new chassis design.
"Yes, it was a chassis change but no I can't divulge the reasons why we changed the chassis," Green said.
He added that the main development focus had been on adapting to new aerodynamic regulations, which restrict the size of the floor, rear brake ducts and diffuser strakes in an effort by the FIA to cut downforce levels and slow the cars.
"I think the main drive in performance is aerodynamics, so there's obviously a big push on the aerodynamic side," Green said.
"The regulation change that came through late last year had a big effect on the aero performance and we spent the winter trying to try to recover the losses from the changes in the regulations.
"That's been a big focus."
As a customer team, Aston Martin is also allowed to update its gearbox and rear suspension from Mercedes' 2019 design to the specification used by the world champions last year without spending development tokens.
Green said that had been part of the team's long-term plan and should bring a step in performance.
"The advantage will be shown, hopefully, when we start running," Green added. "It's a change that had been planned right from the very beginning before we'd even went into the regulation alterations to lock down the cars and try and carry over as much of the car as possible.
"So it's something we had already agreed on, we'd already had visibility of the geometry of the changes. So we were able to start work in that area, relatively early.
"I think we were comfortable with the timeframe for the change in the gearbox which is effectively what it is, it's changing the gearbox.
"I think what was harder was the late change to the aerodynamic regulations. That was the one that required us to react faster. None of that was planned, so like everyone else that came as a shock from the FIA.
"So I think that was the biggest aspect of what we were looking at over the winter, the changes that the FIA have made rather than the planned changes that we already had in place."
Long-term, team owner Lawrence Stroll has targeted championships after investing large amounts of money in a new factory in Silverstone, which should be finished in 2022.
Asked about the target of turning Aston Martin into title contenders, team principal Otmar Szafnauer said: "It's a lot easier to say we're going to be fighting and winning a world championship than actually do it.
"The two things that have to happen are, one, we need a good plan in order to start today and get to world championship contenders and then we've got to execute it.
"We're in the midst of that planning phase now and the execution will definitely take some time.
"People in Formula One, in other teams, have said you've got to give three to five years to do so and we're no different.
"For the last year we've planned a new factory with new infrastructure in a place to house all of us under one roof, to grow the team, and the implementation of that has just now begun at Silverstone and towards the end of 2022 we should be moving into the new factory.
"And within that factory we're going to need state of the art tools that will help us design and develop a car that's worthy of contending for a world championship. That's a few years away.
"If I have to look into the future it'll be in the 3-5 year time period."
The Formula One season will start with the Bahrain Grand Prix on March 28, although there are three days of testing at the same venue between March 12-14.