What's the story? Thai pop singer/actor Krissada Sukosol Clapp has returned to his family's hotelier roots with the help of architect Bill Bensley. Artiste-turned-design director Sukosol Clapp had the vision to transform a 1.2-hectare stretch of land on the banks of the Chao Phraya in Bangkok, owned by his mother, into a luxury 39-suite hotel. After seven years, the result - The Siam - opens fully this month.

What's the design ethos? A mixture of art deco, traditional Thai and colonial vintage that's stunning. There's a dramatic black and white colour scheme with smatterings of dark wood and neutral fabrics. The main hub of the hotel is three vast, interconnected buildings with soaring ceilings, plant and water feature-filled courtyards and light-flooded atriums. They lead out to landscaped grounds where traditional Thai teak houses once belonging to American businessman Jim Thompson sit alongside chic, newly built villas, culminating in a riverside bar on what must be Bangkok's most stylish jetty.

What's with all the vintage touches? The antiques throughout the hotel come from Sukosol Clapp's personal collection and helped shape Bensley's design. There's an abundance of vintage furniture, photographs and silk prints, plus masses of unusual artefacts. A grouping of French horns hangs from the ceiling in the art deco-style bar while, off the lobby, a room featuring a 1930s wooden model car is set aside expressly for the chauffeurs of guests.

What are the rooms like? Even the entry-level Siam suites are chi chi and roomy at 80 square metres, but the pool villas are a knock out; traditional double wooden doors open to reveal courtyards with daybeds in the shade and plunge pools, art deco-inspired interiors and spiral staircases leading up to roof terraces. If you're looking for something romantic, book Connie's Cottage, a traditional Thai teak house once owned by Connie Mangskau, a friend of Thompson's and a fellow OSS (Office of Strategic Services) agent. Rebuilt in the grounds of The Siam, the charming two-storey structure has its own garden and a plunge pool/jacuzzi and just the one bedroom.

If the hotel's a Bill Bensley design, there must be a spa? Absolutely. Take the striking wrought-iron staircase in the main residence down to the cheekily named Opium Spa, where a serene lounge area awaits. From there you'll be escorted to one of the spacious treatment rooms, complete with separate dressing area.

Are there any fitness facilities? There's a svelte lap pool parallel to the river and a slick gym decorated with vintage boxing posters and leather punch bags. While the usual cardio equipment is gleamingly on offer, a more surprising inclusion is a Thai boxing ring, reputedly "the first luxury Muay Thai gym in Bangkok".

What about the restaurants? Choose between Chon Thai, spread over three of the teak houses, and the Deco Bar & Bistro, which is all matt black and mirrors. You can order from the Thai and Western menus in both. The food is superb, especially chef Blair Mathieson's (a New Zealander poached from the Chedi in Chiang Mai) Thai dishes. Standouts include the green mango and soft-shell crab salad, prawn red curry soup and chargrilled beef with chilli sauce.

And bars? As well as the aforementioned art deco number, there's a small and incredibly cute bar in a teak house on stilts, filled with animal-print rugs and antlers on the walls. Reached via a wooden platform, it's like a tree house for grown-ups.

Anything else I should know? In the main residence, there is a private screening room, furnished with antique folding wood and velvet French cinema seats. Here, historic film reels will be shown, and movie nights and a series of guest lectures will be hosted.

The staff at The Siam are the friendliest I've met anywhere - a refreshing change for a "designer hotel".

What's the bottom line? The Siam suites start at 16,300 baht (HK$4,000) per night including breakfast, Wi-fi and butler service.

The Siam is at 3/2 Thanon Khao, Vachirapayabal, Dusit, Bangkok, Thailand, tel: 66 2206 6999; www.thesiamhotel.com