Midfielder joins the Reds
Josh has found his first-team opportunities at The Den limited this season where competition for a midfield berth is stiff with the likes of Nicky Bailey, Shaun Williams, Jimmy Abdou, Jack Powell, Angel Martinez and Ed Upson all jostling for a place in the starting XI.
His loan with The Reds will give 24-year-old Josh the opportunity to get some regular match action for John Gregory's side. He is expected to go straight into their squad for Saturday's League 1 home match with Fleetwood Town.
Millwall have a 28-day recall clause and have given permission for Josh to play in the JPT Trophy, but not the FA Cup.