: Princess Astrid wore an Austrian tiara (or : possibly Savoy from her husband´s : grandmother) when she attended a ball in : Denmark in her younger years. It was later : worn by at least one of his sisters for her : wedding.
Torkel, are you refering to this diamond tiara? It was worn by Princess Margherita of Savoy-Aoste on her wedding to Archduke Robert of Austria-Este (Archduke Lorenz's parents) in 1953 (1st picture below), as well as by Archduchess Maria-Beatrice of Austria-Este on her wedding to Count Ripprand von Arco-Zinneberg in 1980 (2nd picture below) and by Archduchess Isabelle of Austria-Este on her wedding to Count Andrea Czarnocki-Lucheschi in 1994 (3rd picture below):
I don't have seen any picture of Princess/Archduchess Astrid wearing this tiara.