Their happy news was shared by international DJ Diplo, who posted a video of the couple at the alter of a Vegas chapel just hours after leaving the event.
In the shock footage, Joe was seen waiting for his bride for a moment before Sophie joined him wearing a simply tiered white dress and flowing veil.
The Jonas Brothers singer and Game of Thrones star announced their engagement in October 2017 after just over one year together.
They went on to exchange vows for a second time in Europe in July.
The pair married again in front of family and friends at an intimate ceremony at Le Chateau de Tourreau in July in Sarrians, France.
Sophie said at the time her father was thrilled at her choice of husband.
"My dad was beyond pleased when I married a musician because it was always kind of, 'You have to marry a rugby player or a musician.' So I got one of them right ... He's getting into the Jonas Brothers. They weren't his demographic, but he's getting into them now and he loves them and the new music is fantastic," she said.