Naughty Boy's La La La was practically the soundtrack to my summer last year.
The original featured site favorite (*sniggers*) male vocalist Sam Smith, but as he's infinitely more busy since his career has taken off, Naughty Boy enlisted Diva, Leona Lewis, to provide the lead vocals at the 2014 World Music Awards.
Leona did a pretty good job when her voice was within its mid-range, during the verse. However, when she took it higher things went sideways, with her sounding constricted and tight. Honestly, it was a messy showing from the Diva, but I'll cut her some slack. It's not her song, and who knows, she might have been a last minute addition to the performance.