Actress Zelda Williams has leant her support to a ‘yes’ vote in Ireland’s forthcoming marriage referendum.

“As someone who’s grown up with many Irish people in her life, of every orientation (and I'll have yerr guts for garters if you say otherwise!), I hope their fight for marriage equality is successful,” she said in her Instagram post.

“You can do it Ireland! Make history!”

The message of support was made in response to a tweet from Tony- and Golden Globe-winner Ian McKellen.

Earlier this month, he addressed his “friends in Ireland,” saying: “Vote YES on 22 May and make your country first ever to legalise marriage equality by popular vote.”

To friends in Ireland. Vote YES on 22 May and make your country first ever to legalise marriage equality by popular vote. #VoteWithUs

— Ian McKellen (@IanMcKellen) May 1, 2015

Zelda, 25, is the only daughter of the late Robin Williams, who had three children from two marriages.

Before his death from suicide last August, the celebrated actor said: “My children give me a great sense of wonder: just to see them develop into these extraordinary human beings.”

In October, Zelda paid tribute to her father with a tattoo of a hummingbird on her right hand, along with his birth-date, July 21 1951, on her right wrist.