A good song usually requires the fusion and unity of two very different groups of people - the singers/artists, and the producers. The producers help shape and transform the song into something that people will actually want to listen to while the artists provide the vocals, the heart of the song, the instantly memorable and iconic words that will help propel the song further and higher. Of course not every song needs this - plenty of artists go acapella and even more producers are producing their own solo, unaided work to success. With pop music, however, there's a conscious need for a partnership between these two elements - they need each other, they can make each other reach new epic heights. The right kind of partnership can revitalise careers, make instantly catchy ditties and melodies that'll be heard the world over (such as the collaborations between Rihanna and David Guetta) and hell, even have a significant social impact depending on how its used. So here are my top five pop partnerships, although there are many, many more, of the singer/act and the producer who've helped each other to craft and create some seriously awesome and addictive pop songs...