The new Doctor Who companion is to be announced exclusively on BBC One on Saturday night.
The reveal will be made during half-time of the FA Cup semi-final Match of the Day Live: Everton vs Manchester United at around 18.00GMT.
The new companion will star alongside current Doctor, Peter Capaldi, who plays the 12th iteration of the character.
The new companion replaces outgoing character Clara Oswald, played by Jenna Coleman, who was written out of the series in the Christmas 2015 special.
She left the series to take on the lead role in ITV’s major new series on the life of Queen Victoria.
This is the latest change in the drama since showrunner Steven Moffat, who is also behind other hit BBC show Sherlock, announced that he was stepping down from the show.
Broadchurch creator Chris Chibnall has been announced as his replacement.
Doctor Who will return for a new series in 2017.