Portsmouth MP Penny Mordaunt has replaced Priti Patel.
Ms Patel quit as secretary of state at the Department for International Development after failing to declare that she met with Israeli politicians while on holiday.
Here are some key facts about Ms Mordaunt:
:: Her very first job was as a magician's assistant for the president of the Magic Circle.
:: The 44-year-old defeated a sitting Labour MP to take Portsmouth North in 2010, winning 44 per cent of the vote having only previously contested the seat once in 2005.
:: An ardent Brexit supporter, she supported Andrea Leadsom's bid for the Conservative leadership last year, and marched on parliament together with other MPs to show her support.
:: Ms Mordaunt is Royal Navy Reservist, based at HMS King Alfred on Whale Island.
:: In 2014 she appeared on ITV's Splash! raising cash for the Hilsea Lido among other organisations.
:: Ms Mordaunt was previously armed forces minister under then prime minister David Cameron in 2015.
:: Under prime minister Theresa May's government she was appointed as minister of state at the Department for Work and Pensions.
:: She drew criticism - and praise - for her 'smutty' House of Commons speech - during the course of a speech on poultry welfare.
:: Once director of communications at Kensington and Chelsea Council, she caused a stir in the Commons when later as an MP she recalled how a hospital ward in the London borough had been used to film pornography.
:: Ms Mordaunt attended Oaklands RC Comprehensive School and studied philosophy at Reading University.
:: She has worked for the Republican Party in America in 2000, was head of broadcasting for the Conservative Party and had a director position at Diabetes UK.