Secretary of Culture Karen Bradley will replace James Brokenshire as secretary of Northern Ireland.
His appointment follows the resignation of James Brokenshire for health reasons.
Ms. Bradley, 47, has been a deputy from Staffordshire Moorlands since May 2010, and became Minister of the Interior Ministry in 2014.
She was Secretary of Culture since July 2016.
It is the second time that he replaces Mr. Brokenshire in the cabinet after inheriting his position as security minister in February 2014, a position in the Ministry of the Interior, where Theresa May was Secretary of State.
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Mrs. Bradley inherits a difficult situation in Northern Ireland, with Tuesday marking one year since the collapse of the decentralized government in Stormont .
Last January, Sinn Féin's deputy prime minister, Martin McGuinness, resigned from the ruling coalition in protest against the Democratic Unionist Party's handling of a failed green energy plan.
Several rounds of negotiations between the two main parties have failed to reach an agreement.
The mother of two has very little past experience in Northern Ireland, and will have to read herself into a new and complex report, which means an inevitable delay for the start of a new round of negotiations to share power, says the political editor of BBC News NI, Mark Devenport.
He will also have to hold initial meetings with the leaders of the local party and the Tánaiste (Irish Deputy Prime Minister), Simon Coveney.
Ms. Bradley was born in the wastelands in 1970. She attended her comprehensive local school in Buxton and then studied mathematics at Imperial College London.
Before working in politics, Ms. Bradley worked for 20 years in business, serving as an accountant and tax administrator for companies such as KPMG and Deloitte & Touche.
Its official website says that it fought in the parliamentary seat of Manchester Withington in 2005, but it was not chosen for the parliament until 2010, like deputy by Staffordshire Moorlands.
After the 2015 general elections, in which she was re-elected with 51% of the votes, she was appointed to a new role within the Ministry of the Interior – minister to prevent abuse and exploitation.