Shining the spotlight on gilded, glittery gowns and equally glimmering jewelry At Fashion Group International’s Night of Stars in New York City, Girls star Allison Williams (near right) dazzled in a design by one of the honorees, then-head of Lanvin Alber Elbaz: a bedazzled cap-sleeved column gown that glittered from every angle—topped with vintage pieces from Fred Leighton. Meanwhile, at the Spectre premiere in London, French actress Léa Seydoux (far right) pulled out all the stops in a backless silver and gold sequined Prada gown, plus nearly 50 cts. of Chopard diamonds on her ears and her hands. Consider us shaken and stirred.      ON WILLIAMS Pair of Victorian yellow gold hinged bangle bracelets, circa 1890s; price on request; Fred Leighton, NYC; 212-288-1872; fredleighton.com     UNDER $1,000 Femme Forever fleu