“I joined Sinn Fein today,” she announced.
“Because resolving issue number one is the way to resolve all current issues.
“Issue number one is we don't own our country.”
She also expressed her view that the current Sinn Fein leadership should gracefully move aside in favor of younger party leaders without direct ties to The Troubles in Northern Ireland.
“I might not even be the kind of person they want, because I'm gonna write here that I feel the elders of Sinn Fein are going to have to make 'the supreme sacrifice' and step down shortly in the same way the last Pope did.
“It was the smart thing for him to do because his association in people's minds with frightful things meant the church were losing bums on seats, if I may use a showbiz term.
“And now they have barely a seat to spare…
“There'd be a zillion percent increase in membership of Sinn Fein if the leadership were handed over to those born from 1983/1985 onward and no one associated in people's minds with frightful things.”
Gerry Adams has been the president of Sinn Fein since 1983. Mary Lou McDonald assumed the role of vice president in 2009.
The “Nothing Compares 2 U” singer also posted a photo of the seven leaders of the 1916 Easter Rising who signed the Proclamation of the Irish Republic.
After backlash from some of her fans regarding Sinn Fein’s past links to the IRA, O’Connor clarified, “For anyone who is confused, Sinn Fein is no longer associated with the use of violence.”
A number of O’Connor’s followers asked if she was considering running for political office, but thus far she has not responded.
In a statement, Sinn Fein welcomed O’Connor to the party but also defended Adams’ leadership.
"We look forward to working with Sinead in an effort to deliver the changes so badly needed in Ireland,” a spokesperson told the Belfast Telegraph.
"The membership of the party selects the Sinn Fein leadership every year at our Ard Fheis (annual conference)," a spokeswoman said.
"As a member, Sinead would have an equal say in that process.
"In the election in May, Sinn Fein trebled our representation at local government level and elected four MEPs across the island of Ireland.
"Support for Sinn Fein in this state has grown considerably since Gerry Adams was elected as a TD.
"In 2011, Sinn Fein was at 9.9%. The party received 15.2% of the vote in the local elections this year and recent polls have put support for Sinn Fein at between 22% - 26%.”
Adams has yet to comment on O’Connor’s remarks, though he did re-tweet an article about O’Connor joining the party.