Hillary Clinton was greeted with a standing ovation during her surprise appearance at the 77th Tony Awards.
The former US secretary of state highlighted the historical importance behind the musical Suffs, which she is credited as having co-produced, when she arrived on stage to introduce a musical number from the cast.
“I have stood on a lot of stages, but this is very special,” the 76-year-old said.
“I know a little bit about how hard it is to make change so I am extremely proud of this original American musical by Shaina Taub, two time tony winner.”
Ms Clinton used the on-stage opportunity to emphasise the importance of voting, while also noting that it is a US election year.
“Of course it is about some American originals, the suffragists who fought so valiantly for so long to give women in our country the right to vote.
“It is almost impossible to think about what a challenge that was, but now it is an election year and we need to be reminded about how important it is to vote.”
It comes as former president Donald Trump gears to run for president, as he faces pending federal charges for conspiring to overturn the 2020 election, and his recent guilty verdict in an unrelated hush money trial.
Former first lady Ms Clinton lost the election in a shock defeat to Mr Trump in 2016, before president Joe Biden was elected in 2021.
Suffs, a musical which follows the woman’s movement and their “relentless pursuit of the right to vote”, won two Tony awards for best original score and best book of a musical.