Here is some extremely rare film footage of Dmitri Shostakovich as the piano soloist in his own Concerto Opus 35 for Piano, Trumpet and Strings.

Can anyone name the trumpet soloist?

Yes they can! Eminent composer Anthony G. Morris has named the trumpet soloist as the legendary Leonid Yuriev (1913-1971). Mravinsky said of Yuriev, ‘He was the pride of the orchestra. If he were a singer, pianist or violinist he would have been given the highest titles.”