Casemiro insists Antony will prove an important signing for Manchester United.
The Brazilian pair knew each other before they both made summer moves to Old Trafford.
Antony made the switch from Ajax in an £86m deal, while Casemiro left Real Madrid for £60m.
And Casemiro has talked up the quality of his fellow Selecao star.
"I think it's really important to have such a quality player here [as Antony ] with us," he told MUTV. "I knew him from the national team already.
"He'd played with us in Brazil, it's always important to have players of Antony's level. Not just him, we have a lot of top-quality players."