Hughes was thrilled to add a goalkeeper of Cesar's quality to his squad.
"It's fantastic that we've been able to attract a keeper of such outstanding ability to the club," the Welshman said on qpr.co.uk.
"When the opportunity to sign a player of his quality presents itself, you have to act quickly and we've managed to get the deal done.
"It was always my intention to bring two goalkeepers to the club this summer and now we've got fantastic competition in that department."
Hughes added: "He's an outstanding individual, as well as being an outstanding player.
"Not only will we benefit from his ability, but we'll also benefit from his experience and winning mentality."