MOSCOW - A host of celebrity musicians and actors have lined up to endorse Vladimir Putin’s election campaign, raising questions over their motives and rumours of pressure on stars to back the Russian strongman. Putin’s campaign team has broadcast advertisements on television featuring a roll call of Russian celebrities, each given a minute-long slot to explain “Why I am voting for Putin” in the March 4 presidential election. While the luminaries chosen include a number of people who have regularly affirmed their admiration for the premier, the surprise appearance of popular actors known for liberally inclined views has ignited a storm of controversy.