Shawn Mendes Steps Out Shirtless With a Big Smile on His Face

Shawn Mendes looks happy while heating up the Los Angeles autumn ... stepping out wearing a big smile on his face -- and, leaving his shirt at home.

The singer-songwriter was spotted on the sidewalk crushing some boxes he was recycling Tuesday afternoon ... and, it seems he needed to get it done quick, 'cause he didn't even have time to put on a T-shirt.

Kidding aside, Shawn's flaunting his toned chest here ... putting on a show for passersby during his eco-friendly act.

Shawn's tattoos are on full display in these pics -- with the guitar on his right arm and the butterfly on his left drawing attention to his forearms and biceps.

These pics were taken on the same day as his photographed hug with musician Mike Sabath. The two embraced tightly after Sabath helped Mendes with his luggage ... as rumors swirled around the star.

Remember, earlier this week, Shawn addressed the yearslong rumors about his sexuality at Red Rocks Amphitheatre in Colorado ... admitting to the assembled crowd he's still trying to figure it all out.

Mendes called sexuality "a beautifully complex thing" ... adding it's not so easily confined to neat little boxes.