The German soprano, Theresa Nelles, was for 10 years a member in the Mädchenchor am Kölner Dom (Girls' Choir at the Cologne Cathedra), wit who she gained her first experiences a a soloists, appearing in the opera houses of Krefeld, Mönchengladbach and Köln, as well as at the Kölner Philharmonie. For 3 years sh ewas a singer in a jazz band. After completing her high school diploma, she studied singing at the Musikhochschule Köln with Professor Mechthild Georg, and attended master-classes with Professor Kurt Widmer and Krisztina Láki.
Theresa Nelles' first roles included, inter alia, as the First Boy in W.A. Mozart's Die Zauberflöte, Schopfhenne and Frosch in L. Janáceks's The Cunning Little Vixen, Mi in Land des Lächelns by F. Lehar and Lucinde in Der Arzt wider Willen by Charles Gounod.
In 2004, Theresa Nelles appeared at the Internationale Händelfestspiele Göttingen in the opera Rinaldo with Concerto Köln conducted by Nicholas McGegan (CD recording is available); at Bentlager Klosterfestspiele with the Prague Symphony; as Pamina in Die Zauberflöte by W.A. Mozart with the Neuen Philharmonie Westfalen; in W.A. Mozart's Great Mass C minor at he Kölner Dom in the frame of Geistliche(n) Musik am Dreikönigenschrein. She participated in performances of various contemporary composers (among others, Das Floß der Medusa by H. W. Henze, St. Bach Passion by Mauricio Kagel), CD production"Sphärengeometrie" with the Cologne composer Frank Stanzl.
In 2006, Theresa Nelles appeared in Frau Luna by P. Lincke with the WDR Sinfonieorchester Köln conducted by Helmut Froschauer; Die Ehe im Kreis by E. Künneke at the Kölner Oper under Michail Jurowski, as well as X-mal Rembrandt by E. Zádor; Premiere of the reconstruction of the Opernpasticcio by George Frideric Handel, Giove in Argo, as Jagdgöttin Diana at the Markgräflichen Opernhaus Bayreuth (CD-recording is available). From October 2006 to March 2007, she studies in Rome at Conservatorio Santa Cecilia and worked with Maestro Sergio Magli; she gave various concerts in Italy u.a. with the Cologne Dom organist Professor Winfried Bönig. In May 2007 she sang at the Internationale Händelfestspiele Göttingen, Brockes Passion, HWV 48 with the ensemble Musica Alta Ripa. In 2008 she sang Matthäus-Passion (BWV 244) by J.S. Bach, Requiem by W.A. Mozart, Zeitl in Anatevka by J. Bock at the opera housess of Solingen and Remscheid, Carmina Burana By C. Orff.
In 2009, Theresa Nelles recieived her Diploma at the Musikhochschule Köln and admission to the concert exam. She sang Missa in tempore belli by J. Haydn under Marcus Creed; Engagement as Serpina in La serva padrona by Giovanni Battista Pergolesi with the Bochum Symphoniker at Prinz-Regent-Theater, as well as Despina in Così fan Tutte by W.A. Mozart and Sand- / Taumännchen in Hänsel und Gretel by Engelbert Humperdinck at the Werniger-öder Schlossfestspielen; Paulus and Elias by Felix Mendelssohn at the Kölner Dom. WDR production Wiener Blut by J. Strauss under Alfred Eschwé at the the Kölner Philharmonie. In 2010, she sang in Matthäus-Passion (BWV 244) by J.S. Bach alonside Ingeborg Danz. Scenic Kaffee- und Bauernkantate (BWV 211 & BWV 212) by J.S. Bach, as well as engagements at the Theater Koblen as Cupido in Orpheus in the Underworld by J. Offenbach and at Theater Gelsenkirchen as Paulę in Paula und die Rimimos (premiere).
In 2011, Theresa Nelles sang in Johannes-Passion (BWV 245) by J.S. Bach as modern Music-Dance-Theater at the Bonn Kreuzkirche; Elias at the Forum in Leverkusen; Geistliche Musik am Dreikönigenschrein at the Kölner Dom; Glückliche Reise by E. Künneke at the Philharmonie Köln and the Philharmonie Essen with the WDR Sinfonieorchester Köln; The World of the Spirit by Benjamin Britten; Bachfest Bonn with the Orchester BonnBarock. In 2012, she sang in Requiem by W.A. Mozart; The Messiah by G.F. Handel; Markus-Passion by Reinhard Keiser; Die Schöpfung by By J. Haydn; Der Studentenprinz by S. Romberg at the Philharmonie Köln with the WDR Sinfonieorchester Köln; Jazz program at the opening of the BAYER Kultur, Cecilia Mass by Charles Gounod with the Gürzenich-Orchester Köln. In 2013, she participated in concerts for General Electrics, Elias and Psalm 95 by F. Mendelssohn, Baroque programs with the Maternus Consort and the Center for Zentrum für alte Musik Köln (ZAMUS), Weihnachts-Oratorium (BWV 248) by J.S. Bach with Ingeborg Danz and Christoph Prégardien.