First reported by Autosport last month, Ducati has agreed terms with Aldeguer to ride factory machinery from next year.
However, while expected to be with Pramac, the official release from Ducati does not explicitly state what team the 18-year-old will be placed at.
Aldeguer has been one of the top paddock prospects for the last couple of years, with a move to MotoGP in 2025 widely expected after he won five grands prix for Speed Up in Moto2 last season on his way to third in the championship.
He has been linked to several MotoGP rides for 2024, including Honda, but elected to remain in Moto2 with Speed Up to see out the rest of his contract.
Autosport understands Aldeguer's Ducati contract - which runs for two years with an option to extend that until at least 2028 - for his MotoGP debut carries with it a base salary of around €300,000.
"I wish to warmly welcome Fermin into the Ducati family and we can't wait to see him already on the Desmosedici GP," Ducati general manager Gigi Dall'Igna said.
"I am very happy about this agreement because Aldeguer is one of the strongest riders of the new generation of the world championship.
"In the last years, we have followed his evolution and during last season he showed an incredible speed.
"He is a very young guy with fantastic potential and characteristics to do well and we will give him all the technical support to make him grow."
Aldeguer's signing also comes a week on from Pramac team boss Gino Borsoi telling Autosport that he felt like 2023 runner-up Jorge Martin's time with the squad "has come to a bit of an end."
Martin's contract with Pramac runs out at the end of this season, with the Spaniard making no secret of his desire to move to a factory team.
Had he won the 2023 championship, he would have been automatically promoted to the factory Ducati team alongside Francesco Bagnaia.
Aldeguer's signing is the second contract Ducati has inked with a rider in the last two weeks, after agreeing new terms with double world champion Bagnaia through to the end of 2026.
Alongside Bagnaia and Aldeguer, only Honda's Luca Marini and LCR counterpart Johann Zarco, and KTM's Brad Binder have firm deals in place beyond this season.
