Possible Clues:

• Singer with the 2007 hit "1234"
• Leslie ____ (Juno Artist of 2008)
• '1234' singer, 2007
• Canadian with the hit "1234"
• Canadian with the hit '1234'
• "1234" singer
• '1234' singer
• Singer with the 2007 hit '1234'
• Nasty mongrel, in dialect
• Canadian with the 2007 hit "1234"