The Australian will join Miguel Oliveira at the team, who arrives from Aprilia.
Miller was dropped by KTM midway through 2024 in favour of former Tech3 rider Pedro Acosta, who has joined the factory squad alongside Brad Binder.
Pramac will be supported by the factory Yamaha team with a data sharing arrangement in a bid to develop the YZR-M1.
Supporting the factory Yamaha team and Pramac is a dedicated Yamaha test team led by Augusto Fernandez and Cal Crutchlow.
An injury for Crutchlow will keep him sidelined initially with Andrea Dovizioso joining the team in his absence.
“I am so excited to finally start the season,” said Miller.
“The test we had in Barcelona in November was just to dip our toes in the water, but now the real work begins.
“I have had a lot of contact with the guys while they were in Japan working on the M1 and from what I have been told we have a lot of new and interesting ideas and parts to try out.
“The guys seem very excited about this new adventure with Prima Pramac Yamaha MotoGP and the same can be said for me.
“I can’t wait to get on the bike and work hard, trying to make the steps in the right direction to be ready from the first race in Thailand.”
Excited to finally get the season started! The real work begins now and I’m stoked to get back on the bike with @pramacracing and @YamahaMotoGP 💙 A new challenge but with plenty of familiar faces. I feel whole and truly at home with this team 🤟🤩 pic.twitter.com/1BO9qH4Dpp
— Jack Miller (@jackmilleraus) January 31, 2025
Miller returns to the Pramac fold after a spell with the factory Ducati and KTM squads.
He last raced with Pramac in 2020 when it was a Ducati team, but for this year the Italian outfit has switched to Yamaha bikes.
“Coming back to Pramac Racing after a few years is fantastic for me,” said Miller.
“You all know that I have a great relationship with Paolo Campinoti and he, as well as Gino and all the other guys, welcomed me back with open arms.
“It’s a new project for most of us, but it’s so much nicer to start a new challenge like this surrounded by so many familiar faces, rather than having to learn new names.
“I feel whole and truly at home, and let’s hope I have as good a time now, if not better, than in my previous years here.”