Shawn Mendes is celebrating his 21st birthday on August 8.<br />Mendes has gone from a Vine star to the third youngest solo artist to have three No. 1 albums on Billboard's Top 200 chart.<br />He taught himself how to play the guitar by the time he was 13 years old.<br />Despite being an international superstar, Mendes still has a stuffed lion named Leo he carries around with him.<br />Business Insider says he collects guitars and said he has almost 40.
