From 2008 to 2010 he undertook a worldwide cycle of all 32 Beethoven solo piano sonatas, a tour de force which brought him recognition internationally as a musician of the first order.In 2012 Fellner took a one-year sabbatical to dedicate himself to the study of new repertoire and to deepen his knowledge of composition, literature, and film. At the personal invitation of Maestro Bernard Haitink, he briefly interrupted his time-off in the spring of 2012 to perform Mozart’s Piano Concerto No. 22 in E-Flat Major, K. 482 with the Boston Symphony at Symphony Hall. Haitink had first collaborated with Fellner after choosing him to replace an ailing Maurizio Pollini as guest soloist with the Royal Concertgebouw Orchestra in 2010 for performances in Amsterdam and Brussels.Fellner will resume his concert life in January 2013; his upcoming solo programmes will focus on the repertoire of four composers: Bach, Haydn, Mozart, and Schumann. Devoted to the study of contemporary music, he will also present the world premiere of Harrison Birtwistle’s Songs from the Same Earth with his longtime collaborator, British tenor Mark Padmore at the Aldeburgh Festival next June. A recording of Birtwistle’s chamber music is scheduled to be released on the ECM label later this season.