The young couple haven't publicly confirmed their marriage but raised suspicions when they were seen a week ago walking out of a courthouse hand-in-hand in New York City, where it is believed they were married in a civil ceremony.
It is thought that Baldwin and Bieber's stop in London was for Hailey to attend Fashon Week (which also gave Bieber the chance to serenade his beautiful wife outside Buckingham Palace) before they head off to start their honeymoon on the Amalfi Coast.
The couple were photographed dining in a fancy restaurant and spotted by fans strolling around the city of Ravello, looking every bit the honeymooning couple.
While some sceptics are saying the two are just taking some romantic time to themselves before Milan Fashion Week begins, we strongly suspect the pair are taking the opportunity to celebrate their nuptials with some romantic time in the south of Italy.
Married or not, the two lovebirds are certainly enjoying themselves on the Amalfi Coast (and we can't help but be a little jealous).