America/Ukraine (also referred to as AmeriKraine or Supersize Love) is a semi-popular pairing in the Hetalia fandom.
As of 2013, AmeriKraine's popularity is steadily growing. Numerous fan-fictions and fan art have been posted among sites like Tumblr and DeviantART. But it is the Japanese fandom that made the most contribution to it.
The pairing is little justified within the actual series, as Ukraine and America have shown little interaction towards eachother. It has significant historical background, though.