Was once engaged to Queenie Smith.
Was still in love with Sophia Loren when it came time for them to film Houseboat (1958). She went to director Melville Shavelson, in tears, complaining that Grant was chasing her again - she had told Grant she was in love with Carlo Ponti, but he didn't believe her.
Was the only actor Alfred Hitchcock was said to "love." Hitch said that James Stewart was the "everyman", but never cast Stewart after Vertigo (1958) flopped, which he blamed on Stewart now looking too old to draw in the crowds. Ironically, Grant was actually four years older than Stewart.
Was the original choice to play "Rupert Cadell" in Rope (1948), but he was unavailable, so the part went to James Stewart, instead (whom Grant would later replace as the lead in North by Northwest (1959)). Rope (1948) features references to Grant and the earlier Hitchcock film he appeared in, Notorious (1946) with Ingrid Bergman.
Was very close friends with Ingrid Bergman, his co-star in both Indiscreet (1958) and Notorious (1946). Grant was one of the few who supported her throughout her notorious affair with Rossellini, and while Bergman was in exile in Italy he accepted her Best Actress Oscar in 1958.
Was very hurt when he lost his two Academy Award nominations, particularly None But the Lonely Heart (1944), which he thought was his best performance. This is why he was so excited when he accepted his Honarary Academy Award in 1970.
When Sophia Loren visited Los Angeles during the filming of An Affair to Remember (1957), Grant inundated her with dozens of phone calls and hundreds of flowers - even though she had called the affair off.
When his daughter Jennifer was born, he gave wife Dyan Cannon a diamond and sapphire bracelet as a keepsake.
Writer Sidney Sheldon used Grant as the prototype for Rhys Williams, a character in the novel "Bloodline."