The singer and his model wife just dropped a whopping $25.8 million on a massive home in the rich and star-studded Beverly Park, an insanely exclusive Beverly Hills gated community ... where they'll live right across the street from Magic Johnson.

The 11,000-sq. ft. mansion comes with 7 bedrooms and TEN bathrooms, sitting on a 2.5-acre estate up high in the Bev Hills mountains.

Among the highlights -- besides the obvious -- checkerboard stone floor in the foyer, a chef's kitchen, a library that opens up to a garden, a master suite with its own patio, a home gym, a movie theater, an outdoor fireplace, and infinity-edged swimming pool, a koi pond ... and a full-size tennis court.

Along with Magic ... some of their other new neighbors include Sofia Vergara, Sylvester Stallone, Eddie Murphy, Rod Stewart and Denzel Washington.

The Biebers still own a 6,132-square-foot, 5-bed, 7-bath Beverly Hills property they bought in 2018 for $8.5 million. However, like we first told you, they were quickly looking for a new place in L.A. to plant roots ... and Justin casually posted about selling it in October.