The group, which operates a Hotel du Vin in the city already, has started work to turn the 71-bedroom property into its 14th Malmaison with restaurant.
Work to turn the hotel into a Malmaison expected to be completed in the next few weeks with the property to be given Malmaison's signature touches.
Scott Harper, COO Malmaison, said: "We are delighted to reveal that the Seattle Hotel Brighton will re-brand as a Malmaison. The vibrant setting of Brighton’s marina and wider Brighton and Hove area community is an ideal fit for our famous lifestyle brand. We can’t wait to get started.”
Malmaison Brighton is one of four Swire Hotels properties Malmaison Hotel du Vin Group acquired last year in a deal worth £36m.
The company already operates a hotel in Brighton city centre under its Hotel du Vin brand.