Everton confirmed the signing of Besiktas striker Cenk Tosun at half-time of their FA Cup game on Friday.
The deal had been widely expected, and a day earlier manager Sam Allardyce said a deal -- reportedly valued at £27 million -- would be done soon.
Everton had been hopeful that Tosun would be available to face Liverpool on Friday, but the 26-year-old was not in the squad and the deal was not announced until half-time -- with the Toffees trailing 1-0.
Tosun signed a four-and-a-half-year deal, with the move coming just hours after Everton confirmed the transfer of Ross Barkley to Chelsea.
Tosun moves to Everton after scoring 41 league goals in 96 appearances for Besiktas since the start of the 2014-15 season, including 20 goals last campaign.
He had eight goals in 16 games so far this season, and added another four in the Champions League -- three against Monaco and another at Porto.
"It feels great to be an Everton player," Tosun told Everton's website. "I'm really happy to be here and happy that everything is done. I'm really excited to play for Everton as soon as possible. Everton is a great club with a big history and a big culture and I'm looking forward to showing the fans the kind of player I am.
"I bring my skills here and everybody is going to see what kind of player I am. I believe I can be a good player in the Premier League for Everton.
"The Premier League is a strong league, I know that, so my own physical strength will help me. Also I can use both feet the same and I believe I am a good striker in the box."
Tosun, who said he would be available to face Tottenham in the Premier League next Saturday, added that Allardyce was a major factor in his decision to join Everton.
"He said he really wanted me here and to feel that, of course, is another big reason to come to Everton," Tosun said of his new boss.
Tosun was born and raised in Germany and played for their youth international teams but chose to switch to Turkey and has 25 appearances for their senior side, including at Euro 2016.
A product of the Eintracht Frankfurt youth system, Tosun moved to Turkey with Gaziantepspor in 2011 and played three years there before signing for Besiktas.
"This lad looks like he is strong mentally and has a good pedigree," Allardyce said in a statement. "He is Turkey's No. 1 striker and has scored goals in the Champions League and the Turkish League but he is desperate to play here in the Premier League.
"He is an all-rounder, with good movement. He is two-footed, perhaps not the biggest but he's very efficient in the air and in the box he gets good space to get his head on the ball.
"We looked at the qualities of the player, his talent and goal scoring, and his resilience, too. I do not think you can look any more than we have done and, for the price, he is the best in Europe at the moment."
Besiktas president Fikret Orman said his club were "working on a replacement" after accepting that Tosun wanted to move to Merseyside.