well, eight years ago, he was leading protestors in song during ukraine's revolution, and now, he's put down his guitar and he is fighting on the front lines to save that independence from a russian invasion. here's cnn's sam kiley. >> reporter: singing to protestors in kyiv's independent square eight years ago as a rock star, he helped drive a pro-russian president from power. now, the lead singer is in uniform fighting vladimir putin's invasion the old-fashioned way.