However, he returned to Chicago in 1958 to conduct Tristan once again, this time with the Chicago Lyric Opera and soprano Birgit Nilsson.
Harry Nilsson | Birgit Nilsson | Birgit Hein | Lisa Nilsson | Inger Nilsson | Erik Nilsson | Birgit Prinz | Birgit Großhennig | Birgit Bidder | Roland Nilsson | Rob Nilsson | Nilsson Sings Newman | Harry Nilsson's | Birgit Vanderbeke | Birgit Schuurman | Birgit Minichmayr | Birgit Cullberg | Anna Nilsson Simkovics | Torbjörn Nilsson | Sven Nilsson | Nilsson | Nils Oskar Nilsson | Martin Nilsson | Leopoldo Torre Nilsson | Lennart Nilsson | Kent Nilsson | Josefin Nilsson | Ernst Nilsson | Dennis Nilsson | Birgit Strøm |
She made her debut with the company on February 22, 1965 as Ortlinde in Richard Wagner's Die Walküre with Birgit Nilsson as Brünnhilde, Jon Vickers as Siegmund, Leonie Rysanek as Sieglinde, George London as Wotan, and Irene Dalis as
She later drew notoriety for obsessively stalking opera singer Birgit Nilsson for nine years; beginning at the summer of 1968 at the Bayreuth Festival and ending upon Theobald's suicide in 1977.
Hunter's later Metropolitan Opera performances of Die Walküre in 1975 featured Birgit Nilsson as Sieglinde and were conducted by Sixten Ehrling.
Other well known vocalists who endorsed the initiative include Shirley Verrett (soprano), Joan Sutherland (soprano), George Shirley (tenor), Luciano Pavarotti (tenor), Sherrill Milne (baritone), Fedora Barbier (mezzosoprano), Grace Bumbry (soprano), Elly Ameling (soprano), Peter Schreier (tenor), Birgit Nilsson (soprano), Dietrich Fischer-Dieskau (baritone), Kurt Moll (basso), Marilyn Horne (mezzosoprano), and Ruggero Raimondi (basso).
In 2003 Verena Wagner Lafferentz attended the International Richard Wagner Congress held in Copenhagen, attending as guest of honour a performance of Die Walküre by the Royal Danish Opera with Queen Margrethe, Prince Henrik, the patron of the Wagner Congress, Wolfgang and Gudrun Wagner, and Birgit Nilsson.