Rovers have completed the signing of Swedish U21 international goalkeeper Pontus Dahlberg on a season-long loan from Premier League side Watford.
The 22-year-old arrives at the Keepmoat Stadium on the eve of the new season.
The 6ft 4in stopper played 47 times for IFK Göteborg in Sweden, including once in the Europa League, and attracted interest from a host of clubs which eventually saw him move to Vicarage Road.
Dahlberg is a Swedish youth international at U21, U19 and U17 level.
He spent last season back in Sweden with BK Hacken, and is now set for his first taste of action in the EFL.