Former President George H Bush and his wife, Barbara, have served as two of the official witnesses at a same-sex marriage ceremony of two long standing friends.

The weekend wedding of Bonnie Clement and Helen Thorgalsen took place in Maine.

Ms Clement told the Washington Post: “This is such a wonderful time for change in our legal system. Who would be best to help us acknowledge the importance of our wedding as our friends and as the former leader of the free world. When they agreed to do so we just felt that it was the next acknowledgment of being ‘real and normal’.”

The Bush family’s spokesman said that they attended the marriage as private citizens. Mr Bush wore one red and one blue sock as he signed the couple’s paperwork.

Speaking to ‘CBS This Morning’ on 25 April this year, journalist Charlie Rose asked Mr Bush’s son, the former President George W Bush about his 2004 endorsement of a constitutional amendment to ban same-sex marriage.

“Yeah, well, I’m not, I’m not weighing in on these issues, as you know, because I’ve made the decision to get off the stage,” Bush replied. “And so I’m off the stage.”

Laura Bush, who has famously disagreed with her husband on the issue of marriage equality, announced her support for the measure in 2010, during an interview on CNN.

Barack Obama became the first sitting US president to back marriage equality in May 2011.