Sydne Rome was interviewed on the Italian DVD too. I thought her face looked a little strange - botox maybe?
Forgot to mention earlier that English language dubber Richard McNamara makes an appearance in this as the American tourist who turns up at the villa with his wife,very recognisable voice (Polanski used live sound in parts of it) that dubbed John Bartha's character in EYEBALL and CANNIBAL FEROX and loads more i can't remember at the moment (where Johan? 
).
Yeah, Richard McNamara is one of the real pillars of the dubbing scene and his dubbing work goes back to the 1950s - he was Steve Reeves voice in HERCULES (1958) although this was later re-dubbed in America. He is credited with the English versions of numerous peplums and often did the opening narration in these films but I remember him better for his later work. In addition to those John Bartha dubs, he also dubbed Franco Moraldi in DEATH WALKS AT MIDNIGHT (1972), Eolo Capritti in EMANUELLE'S REVENGE (1975), Tom Felleghy in SEVEN BLOOD-STAINED ORCHIDS (1972) and SYNDICATE SADISTS (1975), Don Powell in BLACK EMANUELLE 2 (1976), Adolfo Celi in LIVE LIKE A COP, DIE LIKE A MAN (1976), Carlo Gaddi VIOLENT NAPLES (1976), Franco Ressel in STAR ODYSSEY (1978), the professor in the opening scene in HELL OF THE LIVING DEAD (1980), the butler (Claudio Zucchet) in BURIAL GROUND (1981) and many others.
McNamara was bilingual so he also dubbed films in Italian - typically voicing American characters. He also had many roles on camera - in addition to his IMDb credits he also played an American general in THE DAY THE SKY EXPLODED (1958) and an ambassador in NOTTURNO (1983) etc.
Oh, and the woman who plays McNamara's wife in WHAT? is Cicely Browne, who also worked in dubbing. It's fitting to see them as a couple as McNamara usually hired Browne to dub the female leads in films where he directed the dubbing. For example, she did Scilla Gabel in MILL OF THE STONE WOMEN (1960), Susanne Loret in ATOM AGE VAMPIRE (1960), Chelo Alonso in ATLAS IN THE LAND OF THE CYCLOPS (1961) etc.
Personally, I remember her more fondly for dubbing older female characters in the 70s and 80s - Maria Tedeschi in THE CASE OF THE BLOODY IRIS (1971), Eleonora Morana in WHAT HAVE THEY DONE TO YOUR DAUGHTERS? (1974), Clara Calamai in DEEP RED (1975), Alida Valli in PERFECT CRIME (1978), Adelaide Aste in CITY OF THE LIVING DEAD (1980), Veronica Lazar in THE BEYOND (1981) etc.
