Atop the celebrated W Residences Hollywood, the developers are now marketing for sale one of the largest residences available anywhere in the world, and the most expensive apartment on the market in California. In this week’s “Layouts We Love” column, we take a look inside the 25,000 square feet (2322 square meters, or around half an acre) home with a price tag of US$45 million.

Richard Robertson of Robertson Partners Architects – noted as a Star of Design 2003 and winner of the prestigious French cultural prize “Chevalier de l’Ordre des l’Arts et Lettres” – has proposed a masterful interior floor plan that combines dramatic entertaining spaces with ingenious details and insight into how we live and entertain today. The penthouse can be built out to his specifications, customized for the buyer, or delivered as raw space. Either way, this residence will certainly make a palatial residence for even the City of Angels’ biggest stars.

The gigantic home is entirely on the building’s top floor, the 15th, and the suggested floor plan embodies a level of grace and elegance rare in apartments of this size. Indeed, Robertson felt inspired by the Art Deco buildings of New York architects Rosario Candela and James E. R. Carpenter from the 1920’s. Known for their superb proportions and flow between entertaining rooms (particularly for large parties), these homes have become some of the most desired in New York. Robertson’s plan extracts these key components, updated for today’s modern lifestyles and adapted for indoor-outdoor California living.

Stepping off the elevator into the home, one is led into a large reception hall with statuary niche, measuring nearly 300 square feet (28 square meters). From here, an extensive art gallery with 10-foot ceilings leads to one of the largest ballrooms in any private home in the United States. The expansive entertaining rooms can comfortably host gala events for up to 250 people, and feature a fireplace, full bar with wine storage for around 3500 bottles, and 10-foot walls of floor-to-ceiling glass opening onto setback terraces. The home’s entertaining wing also includes a formal dining room for 20 with its own fireplace, as well as a more intimate morning room. Guests can use either of the men’s and ladies powder rooms, but the remainder of the home can be locked off if the crowd includes rowdy rock stars.

The private residential portion of the home functions perfectly well for a multi-tasking celebrity family, integrating various functions – casual living, home office, fitness, and family life. A double living room is one of the centerpieces of this portion of the penthouse, divided into a family room with a sunny south-facing terrace, and its own trophy room with walls of display cases to showcases your Oscar’s, Grammy’s, Tony’s or Emmy’s – all with a direct view to the Hollywood sign.

As this is Hollywood, the family room leads to a private screening room equipped with sound insulation, professional sound systems, and 3D capabilities. There is also a spacious private fitness center of around 600 square feet (56 square meters), with its own spa, Jacuzzi, massage room and steam room, as well as a beauty parlor for professional hair and makeup. To ink those Hollywood deals, the penthouse’s library sets the tone with its “divine” proportions and centered fireplace. To help deals get made, there is an adjacent pub-style tap room bar, and for the paperwork, a large adjacent office for up to 3 assistants – although some may just dial the concierge for W’s Whatever/Whenever Service.

At 4000 square feet (372 square meters), the master suite is worthy of both the word “master” and “suite.” This ideal series of five rooms includes a separate sitting room, gigantic bedroom with fireplace and cozy bed alcove. The dressing room alone measures over 660 square feet (62 square meters), arranged around a central chest with banquette seating, while the adjacent bathroom is of Roman scale with dual water closets and views toward the Pacific Ocean.

For those buyers with families or live-in staff, three additional bedroom suites are well integrated into the floor plan, along with discreet service areas and at least 20 additional storage closets. For those who love their cars as much as their rooms, the home also comes with 17 valet parking spaces. And naturally, the home features a superb, oversized, professional-grade kitchen, should the residents ever tire of in-room dining or the chic options at the hotel.

The Residences at the W Hollywood are now 60% sold, so should any buyer need more than the 25,000 square foot penthouse, they could always pick up another unit downstairs. This spectacular home is listed with Aaron Kirman of the John Aaroe Group in Beverly Hills along with Ron Barnes of PowerPlay Destination Properties, and can be delivered at the specification of the buyer, although we feel that the Robertson celebrity plan would certainly be our choice.