It's a Boy Girl Thing (2007)

Once upon a time two very different families had two very different babies. Stan and Della Deane, blue collar workers and proud owners of "Spatula City" emporium had Woody. Sporty, outgoing and popular, Woody grew into the all-American football star with all the perks you would expect including the prettiest cheerleader on his arm. The Bedworths had Nell. Pretty, but bookish and unbelievably prim, she is the very opposite of Woody in thought and word and deed. Normally their two paths would never cross, let alone intertwine but fate has dealt them a cruel hand - they're next door neighbours.

Official website: http://www.iconmovies.co.uk/itsaboygirlthing