Diddú's most recent album, Hvert Örstutt Spor (Each Tiny Step), was released in 2005.
Diddú began her singing career as a vocalist with the folk and pop group Spilverk Þjóðanna between 1975 and 1978 and made numerous recordings of folk and popular music, before turning her focus to classical music, particularly Lieder and operas. With the Icelandic Opera she has performed the parts of Susanna in The Marriage of Figaro, Gilda in Rigoletto, Papagena and the Queen of the Night in The Magic Flute, Lucia in Lucia di Lammermoor, Violetta in La traviata, Adina in L'elisir d'amore and Rosalinda in Die Fledermaus. She was a guest singer as Susanna in The Marriage of Figaro in Trondheim, Norway, and as Gilda in Rigoletto in Gothenburg, Sweden (1992). She has also sung the role of Olympia in Les contes d'Hoffmann (The Tales of Hoffmann) at the Þjóðleikhúsið (Thjodleikhusid, or National Theatre of Iceland) in Reykjavík.
In 1994, Diddú appeared in Bíódagar (Movie Days) by Icelandic film director Friðrik Þór Friðriksson, playing the mother of a young boy living in the 1950s who is engrossed with American movies.
On 26 September 2007, Diddú was a special guest of Garðar Thór Cortes at a concert at the Barbican Centre in London with the National Symphony Orchestra conducted by Cortes's father, Garðar Cortes. She performed "Il Bacio" ("The Kiss"), "Mein Herr Marquis" ("My Lord Marquis") from Johann Strauss II's Die Fledermaus (The Bat, 1874), the cavatina "Casta diva" from Bellini's Norma (1831), and "É strano... sempre libera" ("It's Strange... Ever Free") from Verdi's La traviata (1853); and duetted with Garðar Thór Cortes in "O soave fanciulla" ("O Gentle Maiden") from Puccini's La Bohème (The Bohemian, 1896), in a duet from Act I scene 5 of Verdi's Rigoletto (1851), and in "The Prayer" (c. 1999) by Carole Bayer Sager.
| Year(s) of appearance | Production | Role | Awards and nominations |
|---|---|---|---|
| 1992 | Rigoletto (1851) by Giuseppe Verdi | Gilda | |
| 2006 | Le Pays (1912) by Joseph Guy Ropartz Reykjavík Arts Festival 2006, Reykjavík Art Museum, Reykjavík | ||
| [date unknown] | Les contes d'Hoffmann (The Tales of Hoffmann, 1881) by Jacques Offenbach Þjóðleikhúsið (Thjodleikhusid, National Theatre of Iceland), Reykjavík | Olympia | |
| [date unknown] | L'elisir d'amore (The Elixir of Love, 1832) by Gaetano Donizetti | Adina | |
| [date unknown] | Die Fledermaus (The Bat, 1874) by Johann Strauss II | Rosalinda | |
| [date unknown] | Lucia di Lammermoor (1835) by Gaetano Donizetti | Lucia | |
| [date unknown] | The Magic Flute (1791) by Wolfgang Amadeus Mozart | Papagena/The Queen of the Night | |
| [date unknown] | The Marriage of Figaro (1786) by Wolfgang Amadeus Mozart | Susanna | |
| [date unknown] | La traviata (The Woman who Strayed, 1853) by Giuseppe Verdi | Violetta Valery |