Justin Bieber's leaving his mark on the Toronto Maple Leafs -- the "Ghost" singer just designed a special Drew House jersey for his beloved team ... and they're actually wearing them in a game!!
The Leafs announced the collab on Tuesday ... saying Auston Matthews and Co. will wear the sweaters for their Next Gen game on Wednesday as a way to "celebrate" the youth and "future of hockey."
The jerseys are super-unique -- they're black and blue with a shibori-inspired print and Toronto skyline stitched into the arm bands and socks.