Russian champions Zenit St Petersburg announced a major double signing on Monday, with Brazilian international attacker Hulk arriving from Portuguese giants Porto and Belgium midfielder Axel Witsel signing from Benfica.
Both players have signed five-year contracts.
The deal for Hulk was the first to be revealed, with Zenit's club site announcing: "Congratulations to all of our supporters, to all of our fans, Hulk joined Zenit."
No financial details of the Hulk deal were disclosed, though Russian daily Sport Express reported, referring to an unnamed Zenit club source, that Zenit would pay Porto around 40 million euros ($50.4m) in several instalments over three years.
However, the player's agent, Teodoro Fonseca, told Portuguese agency Lusa that the fee was 60 million euros.
The 26-year-old, who has won three Portuguese titles and the 2011 Europa League trophy with Porto since joining from the Japanese J League in 2008, has scored five goals in his 14 international appearances.
Among the clubs who declared an interest in Hulk during the close season were Champions League holders Chelsea.
The Russian giants later signed Belgian international midfielder Witsel for a confirmed 40 million euros from Porto's bitter domestic rivals Benfica.
The 23-year-old had joined Benfica from Standard Liege in July 2011 for 8 million euros.