West Brom have confirmed the signing of Matheus Pereira from Sporting Lisbon.
The 24-year-old forward spent last season on loan at the Baggies and has signed a four-year contract ahead of their return to the Premier League.
He triggered a permanent move for £8.25million in June after making his 30th start of the season and Albion have now rubber stamped the deal.
Sporting and technical director Luke Dowling said: "While there has never been a question that Matheus was our player we decided to leave the final details until the season was complete.
"We wanted Matheus to focus on his football and the last nine games of the season. We agreed out of mutual respect, between club and player, to finalise his contract in the close season.
"Everybody is aware of the impact he made in his first season and from speaking to him I know he is now very excited by the challenge of playing for Albion in the Premier League."
Pereira scored eight goals and grabbed 16 assists in his debut season in England.
He is part of Bilic's squad revamp with Albion prepared to offload Kieran Gibbs as they search for a new left back.
The Baggies ended a two-year exile from the top flight last month after clinching promotion on the final day of the season.
They finished second in the Sky Bet Championship, 10 points behind champions Leeds, following a 2-2 draw with QPR in their last game.
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