The 26 year old says former Feyenoord team-mate De Guzman encouraged him to make the move to South Wales.
He said: "I spoke with Jonathan about the club and all he said was positive things.
"He talked very fondly about the people, players and fans here.
"And, of course, the style of football here is very, very attractive. I love this style and it was a big attraction for me.
"I'm looking forward to working under Michael Laudrup, who is a massive name in football, and showing him what I have to offer.
"Playing in the Premier League is something I have always wanted to do - it's the best league in the world.
"I'm sure I will fit in very well because I share the same philosophy as the club. Having started my career in Ajax's Youth side, I see the style of play here is one that has a real Dutch and Spanish mix, and that will really suit me.
"I can't wait to work hard in training and try to force myself into the starting XI."