Just because it was Mother's Day, that doesn't mean Justin Bieber's mom got ALL his attention at Sunday's Los Angeles Clippers game -- he still found time to catch a glimpse of the hottie a few seats over.
Bieber snuck a peak while his mom was turned around, but you have to wonder if Biebs noticed the GIANT rock she was sporting on her ring finger.
Baby, baby, baby ... OH!!!
Turns out the woman in the photo is Scooter Braun's fiancée -- and Scooter is sitting on the other side of her. So ... definitely not cool, Justin. Not cool.