Related Clues:

• 'You know who this is'
• Reply to "Who's there?"
• Call from behind closed doors
• 'I'm at your service'
• Reply at the door
• Unhelpful knock follower
• 1972 No. 2 single about a manipulative lover
• 'You know who I am'
• Exclamation upon removing a mask
• Arrival's announcement
• Potentially unhelpful answer to 'Who's there?'
• 'I'm here'
• 'At your service'
• Answer from behind a door
• Identification assuming familiarity