The deal will see an option to buy the young forward in January, for a reported £6 million according to 'Sky Sports'.
A youth product at the club, Brereton has made over 50 appearances in the Championship over the past two seasons and dcored on 9 occasions.
He is also an England U-19 international and was part of the team that won the 2017 U-19 European Championship, finishing as joint-top goalscorer in the tournament.
Brereton will join up with the Blackburn squad soon it is thought, along with former Sunderland midfielder Jack Rodwell who has signed with the club until the end of the season.