Details have emerged of Foster + Partners' proposed London hotel project with French luxury conglomerate, LVMH.

According to documents recently submitted to Westminster City Council, the architects are planning an 83-key Cheval Blanc hotel on Grafton Street in the heart of Mayfair.

The estimated £500m (US$636.3m, €570m) property, which is being developed by O&H Grafton, will also feature an underground spa, a restaurant, a rooftop bar and terrace, six residential units, and various retail shops.

The spa wing will boast multiple treatment rooms, a 25-metre pool, and a gym.

Additionally, the scheme will include a variety of outdoor "oasis" areas and an "accessible streetscape" with public art installations.

Foster + Partners and LVMH declined to comment on the plans.

LVMH, which currently operates four Cheval Blanc hotels, recently acquired Belmond Hotels for a reported £2.3bn.

Through its Bvlgari brand, the company also boasts hospitality assets in five different countries.