Pierre played alongside Loovens when the defender signed for Feyenoord at the age of 17 and Pierre feels that his former teammate will become a star at Celtic.
"Celtic are perfect for him and he will be an excellent signing for them," he told the Sunday Mail. "Glenn was just 17 when I got to know him at Feyenoord and I could tell from our first training session he was a no-nonsense defender.
"When he was coming through the ranks we would often have practise games in training between the first team and younger players. Of course I'd be right up against Glenn and he wouldn't hold back."
He continued: "I remember telling him early in his career at Feyenoord he would be suited perfectly to British football.
"Sometimes in Holland we expect too much from our stoppers- we want them to defend, score goals and set up attacks. There is perhaps less pressure to do that in Britain.
"So I've no doubt Glenn will do well and I hope it's another success story for a Dutchman at Parkhead."
Loovens joined Celtic from Cardiff and van Hooijdonk has no worries about him struggling to adapt to life in the green and white.
He said: "He was playing regularly at the De Kuip stadium for Feyenoord in front of 50,000 passionate fans.
"So playing for Celtic is something he will look forward to and be keen to take on.
"He was in the Feyenoord team at Ibrox when we drew with Rangers in the Uefa Cup and also played in our return leg win. That has given him a taste of beating Rangers and I'm sure he will want it much more often now he has joined Celtic."
Whether the Pierre seal of approval will help win over the fans who are concerned that we have spent a large quantity of money on what would appear to be our third choice central defender is yet to be seen. There are many within the support who would have rather seen this cash spent on a first choice left-back as opposed to a 3rd choice target in a position that we have adequate cover in.
Lets hope that this is not the final piece of the jigsaw!
Yours in Celtic
Clydebuilt