Singer Elton John's recent partners on stage, 2Cellos, is consisted of a pair of 24-year-old accomplished cellists from Croatia. Luka Sulic and Stjepan Hauser rose to fame after posting a self-made music video of themselves performing their cover of Michael Jackson's "Smooth Criminal" on YouTube. The clip soon received three millions of views in the first two weeks, and more than five million views in total. Their talents have not only earned them TV appearances, a record deal with Sony Masterworks, but also a chance to join Elton John's tour this summer.