The Bosman signing from Shakhtar Donetsk can't wait to play in front of his new home fans.
"First of all I am very happy to wear a West Ham United kit," Rat told West Ham TV. "I think this kit has a very good quality and is of high standards.
"For me it's an honour to wear this shirt and to play in the Premier League. I will be very proud to wear the claret and blue colours and I hope to satisfy the fans.
"I'll be very excited when I pull on the kit for the first time, because it will be my first game here."