In 2014, Horner wrote Pas de Deux, a double concerto for violin and cello. Commissioned to mark 175th season of the Royal Liverpool Philharmonic Orchestra, the work was premiered on November 12, 2014 by Mari and Håkon Samuelsen, with the orchestra conducted by Vasily Petrenko. Horner also composed Collage, a concerto for four horns, premiered on March 27, 2015 at London's Royal Festival Hall by the London Philharmonic Orchestra conducted by Jaime Martín, with soloists David Pyatt, John Ryan, James Thatcher and Richard Watkins.