Riedewald, 20, capped three times by the senior Netherlands national team, comfortable at centre-back, left-back has agreed to the English Premier League switch on a reported £8million deal - according to Sky Sports.
The Ajax academy graduate was awarded his first-team debut by De Boer at the age 17 and now links up with the Dutchman again - having rejected the advances of Everton.
News of the length of the player's contract will be disclosed at his official unveiling.
Meanwhile, De Boer has completed his first act as Eagles boss by rewarding long-serving midfielder Jason Puncheon with the club captaincy.
"At the beginning, I had a look around and got to know everyone better but I had my information that he would be the best captain and he has proven that in the past three weeks," De Boer told the club's website. "Therefore, for me, there was no discussion; he is our captain.
"He knows the responsibility and what that means, and he has to be an example of what Crystal Palace is."