The Oscar winner is set to bring Kelly back to life on the big screen in new biopic Grace of Monaco, and Kidman's casting has been given the thumbs up from the princess' pal Lynn Wyatt.
She tells People.com, "First of all, I know Nicole Kidman. There is nobody more gorgeous. She's beautiful inside and out, and she's very sweet. She's very nice - and she's caring."
However, Wyatt, a trustee of the Princess Grace Foundation - USA, insists Kelly can never be truly replaced.
She adds, "There was nobody like Princess Grace. I think it's flattering to have somebody play you like that, and, of all people, Nicole would be the right one."
La Vie en Rose director Olivier Dahan has taken charge of Grace of Monaco, an independent film chronicling the European principality's 1962 clash with neighbouring France over tax issues. It is currently in production in France.