Millwall will sign Wycombe Wanderers winger Paris Cowan-Hall when the January transfer window opens.
The 24-year-old has agreed a two-and-a-half-year deal at The Den, with Millwall paying an undisclosed fee.
The deal for Cowan-Hall sees Millwall's Fred Onyedinma extend his loan at Wycombe until the end of the season.
"I think the fans will love Paris. We have been crying out for someone like him - that player who can run with the ball," said Millwall boss Ian Holloway.
"I'm really excited to get him here. He can play wide right, wide left or up front, so he has that mobility and hunger," he told the club website.
"Hopefully it will be the first of many this window because we are going to have to do some business."
Having joined Portsmouth from Rushden and Diamonds in 2007 when Pompey were in the Premier League, Cowan-Hall moved on to Scunthorpe on a free transfer in October 2010, but made just one substitute appearance before moving to Woking the following summer.
After helping Woking to promotion from the Conference Premier, he was for an undisclosed fee and scored five goals in 45 appearances before
Cowan-Hall, who has scored six goals this season, will not be available for Millwall's FA Cup third-round tie with Bradford on Saturday as he is cup-tied.
"I'll be there watching the game, and then next week I'll be training with the squad and hopefully will be involved against Blackpool on 10 January," he said.
"I'm very excited to be here and pleased to have the opportunity to take on the next challenge in my career.
"I'm really looking forward to the rest of the season and I'll be doing everything I can to help Millwall get the results we need to move up the table."