Valtteri Bottas has revealed that the 2013 Williams car will be a 'development version' of the car that saw the Grove-based team return to winning ways in F1 last year.

Having endured the worst season in its history back in 2011, Williams returned to some kind of form last year - winning in Spain thanks to Pastor Maldonado and showing much improved pace, even if Maldonado and Bruno Senna ultimately failed to score as many points as could have been possible.

For 2013, Bottas steps up from the role of test and reserve driver to partner Maldonado and the Finn revealed that much of the focus over the off-season had been on producing a car that has improved aerodynamics while retaining the strengths of the FW34.

"As far as looks, the (2013) car is pretty much as it was last year," he told MTV3. "With the new rules, the step nose is straightened. That is the biggest difference in appearance.

"The new car is a development version of last year's. There are certain improvements in aerodynamics. We have tried to focus on getting more traction in corners."

Bottas also revealed that both he and Maldonado would spend six days each at the wheel of the new car when testing gets underway in Spain next month.