Millwall have signed Josh Coburn on a permanent transfer from Middlesbrough for a "club record" fee.
The 22-year-old scored five goals in 21 appearances for the Lions on loan last season, forming a strong partnership with strike partner Mihailo Ivanovic after Alex Neil took over as head coach.
He has signed a "long-term" contract and becomes the club's second signing of the summer after Max Crocombe's move from Burton Albion.
Coburn departs Teesside with a record of 12 goals in 56 appearances.
"It's no secret that we've been eager to bring him in on a permanent deal," director of football Steve Gallen said.