Justin and Hailey Bieber Twin in Black Outfits for L.A. Date

Justin and Hailey Bieber are proving they still got that yummy yummy for each other ... heading out for a date in Los Angeles Saturday, matching outfits and all.

The couple put on a united front as they walked into the restaurant arm-in-arm ... not breaking a sweat from the unavoidable chatter about the state of their relationship.

JB and Hailey twinned in all black ensembles for their outing ... with the "Yummy" singer rocking an oversized hoodie and Balenciaga sweatpants paired with a pink beanie and Hailey in low-rise black trousers and a cropped tank. She paired her casual look with a black baseball cap with "Rendezvous" written across the the front in red lettering and an oversized bag.

Interestingly enough ... Justin was also videotaped walking into the eatery from the parking lot by himself. He looked laser focused on getting inside, likely wanting to keep a low profile.

The Rhode Beauty founder and her better half have been out and about quite a bit this weekend -- they were also spotted grabbing a sweet treat at a Cold Stone Creamery in L.A. on Friday.

Their son, Jack, did not make an appearance with his famous parents, though the popstar posted an adorable photo of them snuggling on the 'gram Saturday.

Of course ... it's impossible to ignore the recent speculation about their marriage -- especially after Hailey appeared to unfollow Justin on Instagram just a week ago.

Sources tell TMZ it was all a technical glitch caused by Justin briefly deactivating his account.

Justin previously had to address rumors he unfollowed his wife ... claiming in January someone hacked his account and clicked that "unfollow" button.