Brooklyn Beckham Rocks Gay Pride Shirt During Father/Son Gym Sesh

David Beckham's 17-year-old son made a fashion statement on the way into a spin class in L.A. Wednesday -- rocking a pink gay pride tank top ... with the socks to match!

Brooklyn Beckham and his world-famous father hit up SoulCycle for a little father/son workout sesh ... followed by a smoothie at the famous Earthbar cafe.

As for the shirt, it's from Palm Springs Gay Pride in 2011 ... so, we're guessing Brooklyn was just going for more of a retro look.

One more thing ... Brooklyn's currently dating Chloe Moretz.