The deal follows the transfer of Wellington's compatriot Fernandinho from Shakhtar to Manchester City for a fee estimated by British media at 30 million pounds.
"I know this club is used to winning and collecting lots of titles. That was the main reason I came to Donetsk. Besides, lots of Brazilians play here and have a good reputation," 21-year-old Wellington told the club's official website.
The attacking midfielder was named best newcomer in the Brazilian League in 2011 while on loan at Figueirense.
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