"Skylark" is an American popular song with lyrics by Johnny Mercer and music by Hoagy Carmichael, published in 1941.
In this jazzy solo piano version it's arranged for a ballet class "Adagio" exercise and recorded by Peter James on his album "Music for Ballet Class - MORE Songs from the 1940s"
For more info about the album click here: https://bit.ly/3uaJza1