Lewis Hamilton will end his 14-year association with McLaren at the end of the season and switch to Mercedes.
The 27-year-old driver will reportedly sign a three-year deal worth £15 million a year.
According to reports today in several British newspapers, an announcement could come later on Friday.
Hamilton's contract negotiations have been a running saga all season.
More top news
Thursday could be the warmest day of 2017 so far, with temperatures of 22C (72F) forecast, double the average for March.
Former cricketer Andrew Flintoff and Tony Blair's ex-spin doctor Alastair Campbell talk about mental health battles in a series of films.
Row over apparent threat to security co-operation with the EU unless it agrees to a trade deal is a "misunderstanding", a minister has said.