McLaren took the covers off a "completely different" MP4-28 at their Technology Centre on Thursday.
After parading several past title winners out one by one, drivers Jenson Button and Sergio Perez then took the covers of the F1 car that McLaren are hoping will secure this year's crown.
As with last season the new car did not feature the stepped-nose of its rivals', rather it had a sleek slanted nose.
Similar in many other ways to its predecessor, Button says he is eager to get behind the wheel for the first time next Tuesday at Jerez.
"The winter has been long but enjoyable," said the Brit.
"But a Formula One driver wants to get back in a car and feel the speed again.
"It's been an exciting few weeks, building the car and finally seeing it as one late last night."
"It may look like last year's car, but under the skin it's completely different.
"That's why it's so exciting. They've changed enough to make a difference.
"You go into the season aiming to win the World Championship and thats's what we are doing."