What are the most unexpected recordings by major artists outside of their “field”?

To get the conversation going, I will nominate “Anthology of the Zarzuela“ with Igor Markevitch conducting the Orchestra and Chorus of the Spanish Radio and Television on Philips.

Actually, it’s quite hard to say what Markevitch’s field was exactly. By the time he moved to Spain at the end of his career, he had recorded composers as diverse as Berlioz and Berwald. But what characterised all of his previous recordings, I think, was their serious demeanour. Whether he was conducting a “light“ music such as the L’Arlésienne Suites and Verdi Overtures & Preludes or “serious” music such as the Beethoven and Brahms Symphonies, he lavished the same attention on phrasing and balance, and they all come out sounding like a Markevitch recording with punchy brass and percussion, a strong sense of rhythm and heavily contoured dynamics. He also wasn’t much of an accompanist, having recorded few concertos and no operas (although he did record the Berlioz quasi-opera La damnation de Faust). Which made it all the more surprising when this recording of zarzuelas, essentially Spanish operettas, came out.

What are the most unexpected recordings made by your favourite artists outside of their field?