Olivia Newton John and John Travolta just dressed up in their Grease costumes This sweet yellow party dress was first seen in the 1978 , where actress Didi Conn wore it as Frenchie. After that, the dress very likely went into rental stock, where it This sweet yellow party dress was first seen in the 1978 , where actress Didi Conn wore it as Frenchie. After that, the dress very likely went into rental stock, where it 1950s style prom dress for Grease play Zahar Dress Grease Vixen