This cherub or putto peeking over an enormous lute is a favourite for lutenists. I didn't know where it came from, but I am grateful to David Van Edwards who has very kindly told me. He writes:

"It's by Giovanni Battista Rosso (Rosso Fiorentino) 1494 - 1540 and he painted a number of religious pictures featuring a red-headed Christ [Rosso = red, geddit!] It evidently was something of a trademark and this little angel is no exception. He worked for François I in France."