The 67-year-old 'Rocket Man' hitmaker apparently decided to tie the knot with Furnish, 51, after gay marriages were made legal in England recently, reported Daily Mirror.
During John's birthday celebrations at Fizz Las Vegas, Furnish said, "We don't feel the need to take an extra step legally. But since we're committed for life, we feel it's really important to take that step, and take advantage of that amazing change in legislation. We all live by example."
The duo have been in a British civil partnership for eight years.
The couple have two sons, Zachary, 3, and Elijah, 16 months.