Question: In which theater did Heidi Brunner, a Swiss opera singer, play the role as Annio? 

<P0-S0> La clemenza di Tito (English: "The Clemency of Titus"), K. 621, is an "opera seria" in two acts composed by Wolfgang Amadeus Mozart to an Italian libretto by Caterino Mazzolà, after Metastasio. <P0-S1>  It was started after the bulk of "Die Zauberflöte " ("The Magic Flute"), the last opera that Mozart worked on, was already written. <P0-S2>  The work premiered on 6 September 1791 at the Estates Theatre in Prague. <SEP> <P1-S0> Heidi Brunner (born 1966) is a Swiss opera singer. <P1-S1>  She began her career as a mezzo-soprano at the Anhaltisches Theater in Dessau in 1993. <P1-S2>  After making appearances at the opera houses in Basel, Innsbruck, and Biel, she was a member of both the Vienna State Opera and Vienna Volksoper from 1996 to 1999. <P1-S3>  Among the roles she sang in Vienna were Adalgisa in "Norma", Annio in "La clemenza di Tito", and the title role in "La Cenerentola". <P1-S4>  She then sang as a guest artist with theatres throughout Europe, including making appearances at the Bavarian State Opera, the Grand Théâtre de Genève, the Komische Oper Berlin, the Liceu, and the Salzburg Festival. <P1-S5>  In the 2004-2005 season she began performing roles from the soprano repertoire, beginning with a performance of Franz Schreker's "Irrelohe". <SEP> <P2-S0> Phillip Boykin (sometimes credited as Phillip Lamar Boykin) is an American bass-baritone, broadway, gospel, jazz and opera singer, film and stage actor. <P2-S1>  In 2017 he was featured in the Broadway revival of "Sunday in the Park with George" and made Broadway history as the first African-American Boatman/Lee Randolph while reopening Broadway's newest and oldest theater at the time The Hudson Theater New York City which played it last Broadway show in 1968. <P2-S2>  Phillip will play the role of Tonton Julian in the Revival of "Once On This Island". <P2-S3>  He was also featured in On the Town at the Lyric Theater. <P2-S4>  He was nominated for the Tony Award, as well as the Drama Desk and Outer Critic Circle Award for Outstanding Featured Actor in a Musical for his role as Crown in the Broadway revival of (Porgy and Bess). <P2-S5>  He was awarded the Theater World Award for his Outstanding Broadway debut. <P2-S6>  He is the founder and director of "The NYGospel Brothers" a Gospel Quartet that travels around the world spreading the good news. <P2-S7>  One of ten children, Boykin grew up in Greenville, South Carolina. <P2-S8>  He started studies in Opera Performance at South Carolina State College before transferring to the North Carolina School of the Arts. <P2-S9>  He left NCSA in 1990 and moved to the Hartt School of the University of Hartford where he received his Bachelor of Music in Vocal Performance in 1995. <P2-S10>  He later studied toward a Master's degree in Opera and Jazz Vocals from Howard University. <P2-S11>  He was seen on the big screen in Freedom starring Cuba Gooding Jr., Top Five starring Chris Rock and Easter Mysteries written by Tony Award Winning Broadway producer John O’Boyle. <SEP> <P3-S0> Sarah-Jane (born September 26, 1985 in India) is a Swiss demotic singer (schlager, volksmusik) from the Canton of Basel-Country. <P3-S1>  She works with composer Carlo Brunner (brother of Maya Brunner).