Millwall have signed striker Theo Robinson from Huddersfield for an undisclosed fee on a two-and-a-half-year contract.
The 21-year-old had a successful loan spell with the Lions earlier this season.
"I really enjoyed my loan spell at Millwall and felt I settled in well," he told the club's official website.
"Thankfully the manager had faith in me and said he wanted to sign me when the transfer window opened.
"Now I can't wait to get back playing again. This is an ambitious club, and I'm looking forward to helping establish Millwall in the Championship and progress from there."