Possible Clues:

• Boxer, one in Seoul getting whipped -- short task to start with
• Boxer from Seoul I whipped – short task to begin with
• Boxer Billy who sings in French — yes, soprano
• American boxer known as the Brown Bomber
• "The Brown Bomber"
• The heavy weight of royalty was his at last (3, 5)
• Boxer called 'the Brown Bomber'