Eileen Paisley - the wife of the DUP leader - has taken her seat in the House of Lords.
Baroness Paisley of St George's has taken her seat in the Lords
The new baroness from east Belfast entered the Lords just after 1430 BST on Monday.
She and her husband are now one of just four couples to have one spouse in the Lords and another in the Commons.
As a working peer she will contribute to the debate and legislative life of the house - a challenge she said she was looking forward to.
"I'm interested of course in life and death issues - euthanasia, abortion - and I'm interested very much in education," Baroness Paisley said.
"I've always been a worker, so I hope to continue that."
She will be known as Baroness Paisley of St George's, after the ward which elected her to Belfast City Council in 1967.
Her two sponsors were former speaker of the Commons Baroness Boothroyd and former Ulster Unionist leader Lord Molyneaux.
Baroness Paisley is the second of three DUP peers to be introduced after party chairman Maurice Morrow.
The third, former Belfast lord mayor Wallace Browne, will enter the Lords at the end of the month