'Besides a revamped Movistar logo, the "Movistar M" design element on the bike is now white, making it blend in perfectly with Yamaha Factory Racing's aesthetics,' says the team.
This year marks the fifth season the Japanese manufacturer can count upon the Spanish telephone network Movistar as a title sponsor.
Viñales and Rossi will be eager to better their final championship positions of fifth and third in a largely disappointing 2017 campaign.
Rossi said: "I had a great time today. The team presentation is special every year, also for me, because when you see your bike in the new colours, you start to feel excited. During the winter break I always miss riding my M1, and after seeing it today I want to ride it as soon as possible. I only have to wait a few more days.
"Sincerely, I'm looking forward to starting the new season. Last year, I had one win and six podiums, but also some problems and injuries. We want to make our fifth year with Movistar memorable, so this year we will be pushing as hard as we can. The test in Sepang will be important. It's the first opportunity for my guys to get together this year, which will be fun, but we'll soon get serious, because we want to get an idea of our level as soon as possible."
Viñales said: "After more than two months of waiting, we are finally kicking off the new season. I've been working hard to prepare for the start of the new season and I'm looking forward to riding my M1 again. The bike, the new colour scheme, and also the new team logo look good, so judging by the looks of the team, we are ready to begin testing.
"Last year we had a really strong start at the first few rounds and we finished third in the championship. This year we'll try to improve on what we did last year. We have a really good team, so I think it's only natural that we aim for the win in every race and ultimately for the championship title, but of course we'll only achieve this if we stay focused every session and push as hard as we can.
"We'll be giving the 2018 bike a try in Sepang in a few days' time, which is also where we held our last test of 2017. We'll use that data to start the season in the best way possible. The first time you start the engine and hear the sound of your new bike is something special - it will be the sound of the new season. I'm looking forward to a great year."