Aston Villa have agreed a deal with Chelsea for left-back Ian Maatsen.
The fee for the 22-year-old is understood to be to be between £35m and £40m and it will rise with add-ons.
Maatsen will sign a six-year deal at Villa Park and Sky Sports News understands talks over personal terms are now underway, with initial discussions described as positive.
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Maatsen had a £35m release clause which expired earlier this week, allowing Chelsea to negotiate the higher price they agreed with Villa.
Borussia Dortmund were keen on signing the left-back on a permanent deal after his successful loan spell at the Bundesliga club last season. They made offers but fell short of the original release clause.
He made 16 Bundesliga appearances for Dortmund, scoring two goals, and featured seven times for the German club in the Champions League, finding the net once.
Everton closing on Iroegbunam after Villa bid for Dobbin
On top of a deal for Maatsen, Villa want to sign Everton striker Lewis Dobbin and have made an offer for the 21-year-old, who made 12 Premier League appearances and scored one goal last season.
Everton, meanwhile, are closing in on the signing of Tim Iroegbunam from Aston Villa.
Talks for the midfielder are in the final stages and a deal is expected to be completed soon.
Both Everton and Villa are among the Premier League clubs under pressure to sell players to stay in line with Profitability and Sustainability Rules (PSR).
Juventus remain in talks over a deal for Douglas Luiz, but they cannot afford to meet his valuation up front, so the clubs are discussing which players could go in the opposite direction.
Weston McKennie and Samuel Iling-Junior are the Juventus players that have been discussed.
'He wants to play in CL' | How Villa beat Dortmund to Maatsen...
Sky Sports New chief reporter Kaveh Solhekol:
"Maatsen had a release clause in his contract, which Dortmund could have activated.
"That release clause has expired, which meant Aston Villa could make their move and that is exactly what they've done.
"It's crucial that Villa are in the Champions League. The player himself wants to carry on playing in the Champions League.
"He's expected to sign a six-year deal at Villa and it's a very good deal for Unai Emery's side.
"He played so well for Dortmund, helping them reach the Champions League final."
When does the summer transfer window open and close?
The 2024 summer transfer window in the Premier League and Scottish Premiership is officially open.
The window will close on August 30 at 11pm UK time in England and at 11.30pm in Scotland.
The Premier League and Scottish Premiership brought forward Deadline Day to link up with the other major leagues in Europe. The closing dates were set following discussions with the leagues in England, Germany, Italy, Spain and France.