Collins has started all four tournament matches for the Ospreys since joining from Toulon and his inside knowledge on
French opposition could be a real bonus.
"Everyone had heard all the stories about Jerry Collins around the world," said Johnson. "It just goes to show is it myth or legend?
"The reality is you can only judge on what you see in front of you and Jerry has been exemplary.
"In many ways, we treat Polynesian players like they don't have a senior role to play as we interpret their quietness as something else.
"Jerry has a way about it but he is a very bright guy. He's been superb for us. We missed Ryan Jones and the like when he was injured but Jerry has really stood up to the mark both on and off the field.
"There is a presence and an air about him. I'm happy for the team at the moment but I'm happy about the lad and I believe it's an important statement that he makes to the world that there are a couple of sides to Jerry Collins - and one of those is vastly under-rated."
The Ospreys have never gone beyond the quarter-finals stage in six attempts, going down to Saracens in the 2008 quarter-finals and then crashing out 43-9 against Munster at Thomond Park a year ago in their heaviest defeat in 42 Heineken cup matches.
And Australian-born Johnson - who has coached the national teams of Wales and the USA - is now a massive fan of the Heineken Cup.
"I've watched the competition grow since I saw Ebbw Vale and Ulster in the Heineken Cup," he said. "I was trying to draw comparisons with the Super 12 at the time and I thought then that the north would never catch the south.
"But the changes in the competition have been remarkable. It is intense football and extremely good football against quality opposition. It has its own style and uniqueness - there is much to love about the Heineken Cup.
"In some ways the punishment does not fit the crime as some really good sides are going to miss out here but I'm glad to be part of it as we live a privileged life.
"And the competition is getting there as the years go by. The Super 14 has flagged a little bit but the problem with the competitions in the northern hemisphere is they can go on for too long.
"The innovativeness comes from the south because they have shorter seasons. But it's easier to be innovative when you have time on your hands. Super 14 and the like hold the initiative but the south watch intently the north - and especially the Heineken Cup.
"They always seem to know what is going on in the big games and I love the competition, it is wonderful."