As quickly as Selena Gomez blocked Justin Bieber from her life via her telephone and whatnot, they hooked up again … capping off a 24-hour rendezvous at a swanky Beverly Hills hotel. 

TMZ has learned … Bieber had a driver take him to LAX Wednesday night, where they picked up Selena … and rolled over to her home. We’re told Bieber spent the night at SG’s place. 

The next morning, the two hitched a ride to the Four Seasons Hotel in Beverly Hills … but entered the building at separate times, presumably so no one would snap a shot of them together.  

As we previously reported, Selena had been dead set on cutting JB out of her life, even blocking him on her cellphone  … but you know young love — predictably unpredictable.