Mack, yes it's a beautiful solo complementing Billie so brilliantly as he did on that whole series of recordings with her in the late 1930s. My own favourite from the series is When Your Smiling.
For those who don't know, as well as Lady and Prez, the recordings had an all star line up, mostly with Buck Clayton on trumpet, Teddy Wilson's glittering piano and the Basie rhythm section of Freddie Green/Walter Page/Jo Jones. There were other players brought in for some of the records like Johnny Hodges, Benny Goodman, Roy Eldridge, Buster Bailey, Benny Morton. Often the tunes were not the hit songs of the day, these being given to the label's more well known stars, but the musicians on these records turned them all into gems. The sessions were brought together by John Hammond, without whom Jazz in the swing era - and hence all later jazz - would have been much the poorer.
YC