US Supreme Court Judge Ruth Bader Ginsburg is to officiate at a same-sex wedding on Saturday in what is believed to be a first for member of the nation's highest court.
A Supreme Court spokeswoman said on Friday that Ginsburg was to preside over the wedding of Kennedy Center President Michael M Kaiser and economist John Roberts.
Ginsburg, who at the age of 80 is the oldest judge in the top court and one of four progressive judges on the nine-member panel.
The Washington Post newspaper quoted Ginsburg as saying she was looking forward to helping the couple tie the knot.
"I think it will be one more statement that people who love each other and want to live together should be able to enjoy the blessings and the strife in the marriage relationship," she told the Post.
In June, the US Supreme Court voted for the repeal of the defence of traditional marriage, which prevented same-sex couples from enjoying the same rights as heterosexual couples.
It also effectively legalised gay marriage in California. Ginsburg had voted in both cases in favour of marriage rights.
Gays and lesbians can legally marry in 14 out of 50 US States and, since 2009, in Washington.