David Lammy has been appointed the new Deputy Prime Minister following the resignation of Angela Rayner.
Mr Lammy, who was Foreign Secretary before the reshuffle, will take over from Ashton MP Ms Rayner - who stood down earlier on Friday following a row over her tax affairs.
Sir Keir's Cabinet reshuffle will also see Mr Lammy become the new Justice Secretary.
Yvette Cooper has been moved from Home Secretary to Foreign Secretary to replace Mr Lammy, while Justice Secretary Shabana Mahmood has been appointed the new Home Secretary, according to reports.
Mr Lammy had served as Foreign Secretary since July 2024 when the new Labour government took charge.
The veteran MP had previously held junior ministerial positions with previous Labour governments under Tony Blair and Gordon Brown.