Ms Mavis Chionh will be appointed a High Court judge from March 12 next year, three years after she took on the post of judicial commissioner.
The Prime Minister's Office (PMO) also announced yesterday that Mr Kwek Mean Luck, the solicitor-general since 2017, will become a judicial commissioner on Jan 4 next year.
Their appointments will bring the total number of Supreme Court judges to 26, said the PMO.
Ms Chionh, a senior counsel who had served as second solicitor-general in the Attorney-General's Chambers (AGC), joined the legal service in 1991 after graduating from Oxford University.
She has accumulated considerable experience during her postings to the Supreme Court, State Courts and the AGC, the PMO said.
Mr Kwek, also a senior counsel, began his legal career in the Supreme Court in 1998 and was called to the Bar in 2002.
He previously held appointments in the Administrative Service, including deputy secretary (industry) in the Ministry of Trade and Industry as well as dean and chief executive of the Civil Service College.
The PMO also announced that Mr Tai Wei Shyong will be the third deputy attorney-general in the AGC. He will start his three-year term on Jan 1 next year.
The current two deputy attorneys-general are Mr Lionel Yee and Mr Hri Kumar Nair.
Mr Tai had been chief prosecutor in the AGC and assistant registrar of the Supreme Court.
In his more than 20 years in public service, he has held a number of key appointments, including deputy secretary at the Home Affairs Ministry and director of the Internal Security Department.
Attorney-General Lucien Wong said Mr Tai brings deep experience and knowledge of the work of the AGC, having previously served as deputy public prosecutor and chief prosecutor of the Criminal Justice Division.