- Video report by ITV News Political Correspondent Carl Dinnen
Pro-Brexit MP Penny Mordaunt has been named as the new International Development Secretary, Downing Street has confirmed.
Ms Mordaunt was called to No. 10 for a meeting with the Prime Minister on Friday afternnon, after which her appointment was confirmed.
She replaces Witham MP Priti Patel, who resigned earlier this week after it emerged she had held a series of undisclosed meetings with Israeli political figures.
There had been concerns among commenters that whoever replaced Ms Patel - who had also backed Brexit - might upset the balance of support within the Cabinet.
- Read: Who is Penny Mordaunt?
Speaking to the BBC's Today Programme, Iain Duncan Smith said he believed the "balance" of appointing someone with strong views on Brexit was something the Prime Minister would "in all probability" look for.
Ms Mordaunt brushed off questions over whether she was joining a "cabinet in chaos", saying she was "delighted" to have been given the new post.
She said: "I'm looking forward to working with the team here to continue building a safer, more secure, more prosperous world for us all, and really giving the British public pride in what we do."
The announcement marks the second reshuffle in a week for Theresa May.
Portsmouth North MP Ms Mordaunt, a Royal Navy reservist, had been touted to replace Sir Michael Fallon as Defence Secretary when he resigned over allegations of inappropriate behaviour - but she was passed over in favour of Chief Whip Gavin Williamson.
Sarah Newton was also appointed as the new Minister of State at the Department of Work and Pensions, while Victoria Atkins has been made the Parliamentary Under Secretary of State at the Home Office as part of Mrs May's reshuffle.
ITV News Political Correspondent Carl Dinnen said he did not expect the Prime Minister to make any more new appointments on Thursday.
Ms Mordaunt's appointment was largely warmly welcomed by Conservative MPs and aid charities, with even her predecessor, Ms Patel tweeting her "congratulations" to her "dear friend".
Berwick MP Anne-Marie Trevelyan hailed the 44-year-old as a "great choice" and Mims Davies MP for Eastleigh tweeted that she was "an excellent choice", as well as praising the appointment of Ms Atkins.
Ms Mordaunt's former parliamentary private secretary during her time at the Department for Work and Pensions (DWP), MP Huw Merriman, described her as "a great person and a great talent", while fellow DWP parliamentary private secretary Peter Heaton-Jones said she was a "brilliant appointment".
Oxfam chief executive Mark Goldring said he "warmly welcomed Penny Mordaunt's appointment and look forward to working with her to ensure that Britain continues to play a leading role in helping the hundreds of millions of people around the world who are without the basics we take for granted such as food, medicines and a place to call home.
"I trust she will be a champion for Britain ensuring that aid is spent where it is most needed, helping the world's poorest people.
"I also hope she can be a strong voice in Government on issues that hurt the world's poor, persuading her colleagues of the need to tackle tax dodging that costs poor countries countless billions and the need to push for peace rather than fuel the conflict which has left Yemen on the brink of starvation."
Save The Children UK's chief executive Kevin Watkins, congratulated Ms Mordaunt on being appointed to "the best job in Government".
"We look forward to working with the new Secretary of State to help deliver this Government's promise to eradicate poverty and save children's lives," he said.