Park Avenue’s grandest hotel has the splendid spa it deserves — along with a brand-new beauty boutique in its iconic lobby.

The Waldorf Astoria New York reopened last summer after a dazzling eight-year, multibillion-dollar renovation; several months later, the Guerlain Wellness Spa debuted on the fifth floor — and it’s just as impressive.

One of Manhattan’s largest and most sumptuous sanctuaries, the soothing 22,000-square-foot space features 16 treatment rooms (including two VIP double suites), a cryotherapy chamber, an infrared sauna, a steam room, a Moroccan hammam, an arctic snow cave and a retail area.

Spa services include everything from facials, massages and body treatments to makeup lessons.

Spa services range from a two-hour, tailor-made facial treatment to the hourlong Imperial Relaxing Massage, inspired by the brand’s renowned Eau de Cologne Impériale fragrance. Also on the menu: body therapies, experiences for two, makeup lessons, mom-to-be rituals, three-day wellness retreats and more.

“With this opening, we proudly continue our legacy of combining French art de vivre and exceptional savoir faire to redefine the future of well-being,” says Gabrielle Saint-Genis, CEO of Guerlain, the nearly 200-year-old heritage house.

Beside the spa sits an equally state-of-the-art fitness center that offers tech-backed consultations (like a comprehensive analysis using the “Technogym Checkup”) as well as personal training and small group coaching sessions.

Meanwhile, the hotel’s landmark lobby has just welcomed a Guerlain boutique, which carries luxurious perfumery, skin care, makeup, hair care and limited-edition beauty treasures, along with the brand’s new L’Art & La Matière home fragrances. Choose between refillable and customizable scented candles (pair a two-tone decorative jar with one of the six fragrances) and faceted hand and body soaps.

So you can bring home all the pampering.