Joan Collins believes women over 40 should steer clear of jeans.
The 78-year-old actress - who was recently snapped wearing denim jeans with a black leather jacket - insists the style is not for everyone.
She said: "Frankly, [wearing jeans] just makes everyone look the same. One of the things about being glamorous is that you have to find your own look.
"If you must wear jeans, which are rarely glamorous in women over 40, wear dark blue or black and pair them with t-shirts that are fitted or jackets that are classically cut."
Dishing out fashion tips from her new book, 'The World According to Joan', the iconic former 'Dynasty' star
says she was advised by Hollywood actress Claudette Colbert to always pick clothes that suited her.
She told 'BBC Breakfast': "A lot of the best dressed [older women] have defined their look.
"My advice is to find a style that suits you and stick to it."
Meanwhile, Joan mingled with the Hollywood elite at a series of Oscars parties last month, and admits she was impressed by P. Diddy.
She told 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."