Preston Take Man Utd Youngster On Loan.
The 21 year old has previously been on loan at Doncaster Rovers but he was recalled so that he could be loaned out to Simon Grayson's men.
Johnson was born in the Preston area, and is the son of Glenn Johnstone who kept goal for the Lilywhites.
With the arrival of Johnson, Preston will have three players competing for the starting place between the sticks with Thorsten Stuckmann and Jamie Jones already competing.
Johnstone will not be able to appear for North End in the FA Cup or Johnstone's Paint Trophy as he is cup tied in both competitions with Doncaster.
North End manager Simon Grayson told reporters: "This is a lad we have kept our eye on for some time.
"We tried to do something in the summer with him and when a player comes available who you think is going to improve the squad, regardless of what you have already, and you have the green light to go and do it, then it`s something you go and do.
"We believe that he is going to be a top goalkeeper.
"He has been brought up at Manchester United and played for England at youth level and that tells you everything you need to know about him."