I learned of this video from listening to The Economist this morning (Putin’s prevaricating puppets – – RT’s propaganda is far less influential than Westerners fear – – The Kremlin-backed network inflates its viewership with YouTube disaster videos)
Putin actually seems to be mouthing the words as one or more others on stage poorly perform the song.
“The scene was a children’s charity dinner in Putin’s native St. Petersburg. The audience was dotted with the likes of Sharon Stone, Kevin Costner and Goldie Hawn. The crowd cheered him on, swaying and clapping as Putin sang. Stone flashed a peace sign.” (http://abcnews.go.com/International/vladimir-putin-sings-blueberry-hill-charity/story?id=12381482)