Sir Anthony is in self-isolation, but keeping his (and his cat's) spirits up during the pandemic by hitting the keys.
I think that's one of Chopin's Nocturnes but Hopkins is an excellent composer and it might be a pastiche.
CNN rounds up some of the better "isolated celebrity" performances:
Coldplay's Chris Martin has been singing to an empty room, Justin Bieber has been dancing, David Spade has done a stand-up set in his living room, and Ellen DeGeneres has been watching herself on TV.