Wolves have completed a permanent deal to sign Helder Costa from Benfica for a new club-record transfer fee.
The 23-year-old moved to Molineux on loan last summer and has scored nine goals in 29 appearances so far.
He has now made the switch on a long-term basis - with the record fee believed to be £12.8m - signing a contract committing himself to the Midlands club until the end of the 2020/21 season.
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Costa told Wolves' official website: "I am very happy to have signed this deal. I am enjoying every moment here at Wolves.
"Now I want to get back to work and help get Wolves back up to the Premier League.
"The fans have been incredible both to me and to the team. We are going to do our best and keep pushing to the end of the season."
Costa has impressed during his time in the Championship and scored the opener in Wolves' 2-0 win at Premier League Stoke in the FA Cup earlier this month.
He also played a significant part in eliminating Liverpool from the competition at the weekend, providing assists for the goals scored by Richard Stearman and Andreas Weimann.
With that and the fact there had been reported Premier League interest in Costa in mind, recruiting him on a permanent basis is a real coup for Wolves manager Lambert.
The club's previous transfer record was set last summer when Portuguese midfielder Ivan Cavaleiro moved from Monaco for £7m.
Lambert said: "This is great news for Helder, great news for the club, and great news for the supporters.
"For how good he has been for Wolves, Wolves have been great for Helder as well. Going forward this is a big statement by the owners.
"Helder is well respected by everyone at the club and is playing at the top of his game at the minute.
"For the owners and everyone connected with the club it is a big situation for us to get him signed. It is vital for him to keep playing as he is.
"He has got ability - no doubt about it - and if he keeps up the work-rate to go with that ability then he has a big chance to be a really top player."