Cindy McCain, the wife of 2008 Republican presidential nominee John McCain, has posed for an advert endorsing gay marriage rights.

Mrs McCain is shown in the adverts with duct tape across her mouth and ‘NOH8′ written on her cheek. NOH8 is the name of the campaign against Proposition 8, which banned gay marriage in California.

Her daughter Meghan McCain, a Republican who has made no secret of her support for gay marriage, has also been photographed for the website.

She tweeted yesterday: “I couldn’t be more proud of my mother for posing for the NOH8 campaign. I think more Republicans need to start taking a stand for equality.”

Mrs McCain had approached the campaign to offer her help, the NOH8 website said.

In contrast to his family’s support, John McCain’s office said he respected their position but stood by his opposition to gay marriage.

A statement released to Associated Press read: “Senator McCain believes the sanctity of marriage is only defined as between one man and one woman.”

The Arizona senator supported a state voter measure in 2008 which restricted marriage to heterosexual couples.

Text on the NOH8 website said: “Although we had worked with Meghan McCain before and were aware of her own position, we’d never really thought the cause might be something her mother would get behind. We have a huge amount of respect for both of these women for being brave enough to make it known they support equal marriage rights for all Americans.

“Aligning yourself with the platform of gay marriage as a Republican still tends to be very stigmatic, but Cindy McCain wanted to participate in the campaign to show people that party doesn’t matter – marriage equality isn’t a Republican issue any more than it is a Democratic issue.

“It’s about human rights, and everybody being treated equally in the eyes of the law that runs and protects this country. “