Guarda Streamingcommunity. The LSO’s Principal Guest Conductor Michael Tilson Thomas celebrated his 70th birthday in 2015 with a concert focusing on British and Russian music, but with a nod to his native USA. He’s joined by the sensational young Chinese pianist Yuja Wang in Gershwin’s popular Concerto. Michael Tilson Thomas gave the US premiere of Colin Matthews’ Hidden Variables, an LSO commission during Matthews’ time as an Associate Composer with the LSO.