Rangers midfielder Lewis Macleod has agreed a deal to join Brentford on a three-and-a-half-year contract.
The 20-year-old will officially join the Championship side on Saturday when the January transfer window opens.
"I am delighted to have secured such a young talent as Lewis," Brentford boss Mark Warburton told the club website.
"He has had an outstanding season with Rangers and will be an excellent addition to the playing squad."
The Bees are thought to have paid around £1m for the midfielder, who has scored eight goals for Rangers this season and received his first Scotland call-up in November.
Macleod, who has scored as Championship side Rangers beat Premiership opponents St Johnstone and Inverness in the League Cup earlier this season, was named the Scottish Professional Football League's young player of the month in November.
Having broken into the Rangers first team in 2012-13, Macleod made 26 appearances that season and then 21 in 2013-14, netting five goals.
He has been one of the club's star performers this season but interim Rangers manager Kenny McDowall believes his side can cope with the loss of Macleod.
Speaking before the deal was confirmed, McDowall said: "It would be naturally a blow to see him go. He is a talented lad and he's got the opportunity to move on, which looks like it may now be the case.
"It's disappointing to lose him but that is football. You have got to move on.
"Lewis is one of our top players but it is also an opportunity for someone else to come into the team and stake a claim. So nothing has changed. We are still a good team.
"It's not one player which makes our team. We have a lot of good players in that changing room."