I'd hoped for better! This is a weird combination of talents and perhaps miscasting.
Warren Beatty is delightful and irresistable as the romantic lead.
Leslie Caron should have played this role when we loved her in
"The L-shaped Room" ten years earlier. Here she is just too sophisticated, worldly wise, and conniving to be swept off her feet by a wanna be film-maker, who can't pay his rent (yet somehow has an abundance of champagne!).
A word here about the fact that William Peter Blatty of "The Exorcist" fame wrote the screenplay. I know, I know; The theme song is sung by Tom Jones!
I kept feeling disturbed, like when the baby doctor; a suitor and employer of Leslie Caron; a famous child specialist, is preparing a paper on infants feeling robbed of their feces when the toilet flushes it away!!! Not such a light thought...
OR when after a short time alone together, Warren Beatty has the baby of Leslie Caron undressed down to a diaper and appearing in his soft core porn. Also shots of the baby on the potty, or drunk froma mixed up baby formula and other things...
So, Arthur Hiller is directing the humor with cameos by giants like Hermione Gingold and Lionel Stander in another movie world entirely. Light-hearted glib and silly.
It is this contrast between silly and sneaky that makes this film difficult to believe and hard to love.