Rick Springfield, 77, shocks fans with ripped physique during shirtless performance

Rick Springfield is proving age really may be just a number. The 77-year-old rocker stunned fans with his remarkably fit physique while on tour, prompting social media users to marvel over his youthful appearance. Fans flocked to social media to gush over the "Jessie's Girl" singer as a video of him performing in Las Vegas went viral over the weekend. In the video , Springfield plays the guitar and sings while shirtless on stage. LENNY KRAVITZ REVEALS THE SIMPLE TEST HE USES TO KNOW IF HE'S STIL