You probably don't remember Celestina Warbeck (there are throwaway references to her in three Harry Potter books), but she kinda looks like this.
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Basically, like Shirley Bassey. As J.K. Rowling has posted on Pottermore – and shared with Today:
Although we never lay eyes on Celestina during the whole seven volumes of the Potter books, I always imagined her to resemble Shirley Bassey in both looks and style.
Rowling says in the entry that the name Celestina came from a friend with whom she worked at Amnesty International.
today.com
As well as talking about the "glamorous" witch's Hogwarts house, wand, family, and hobbies, Rowling goes on to describe how popular Celestina really is:
Three devoted fans were involved in a nasty three-broom pile up over Liverpool while trying to reach the last night of her Flighty Aphrodite tour, and her tickets often appear on the black market at vastly inflated prices (one reason why Molly Weasley has never yet seen her favourite singer live).
