The 78-year-old actress met a string of famous faces while attending post-Oscars parties last month and was particularly impressed by the hip-hop mogul, actress Sofia Vergara and designer Victoria Beckham.
Joan - who attended the bashes with husband Percy Gibson and sister Jackie Collins - told Britain's Grazia magazine: ''In the ladies loo I spoke to Sofia Vergara, who is a true beauty with a woman's body, not a stick insect like so many of the starlets.
''I also spoke to P. Diddy, who was super smooth and very complimentary to me.
''Percy brought Ben Stiller to say hello and he was taller than I expected. Then I spoke to the Beckhams. 'You're so tall!' I told Victoria. 'Yes I am' she smiled - then revealed her seven-inch heels.''
She added: ''Tom Cruise looked about 30 years old and was super charming. Michelle Williams was sweet and self-effacing. She had the most perfect, line-free skin.
''I got in deep conversation with Tom Ford, who was also charming.''