Jet-setters, hold on to your hats: the Dorchester Group’s legendary Bel-Air Hotel, which Zagat surveyors praise as a “lover’s paradise” where “everyone is treated like a star,” will close for an 18-month renovation beginning October 1. The hotel’s restaurant, which has nabbed Top Decor honors for the better part of the decade, and whose celeb-heavy list of regulars includes the likes of former First Lady Nancy Reagan, will also be closed during that time.