Sterling has impressed during England's training camp ahead of the finals and is tipped to start the weekend's opener against Italy, with Roy Hodgson describing his performance in training last Friday as "breathtaking" and "unstoppable".
The Liverpool winger was forced to miss Saturday's final warm-up friendly with Honduras after receiving a red card against Ecuador and Liverpool team-mates Henderson and Johnson believe that the 19-year-old could be England's surprise package in Brazil.
"Raheem is a fantastic player. I think you've seen that in the Premier League and even when he's played for England," said Henderson.
"Possibly it could make him a secret weapon because he's not played [in the friendlies]. Obviously, he will have been disappointed he could not feature, but in training he has looked very, very good, so he'll be thriving on this.
"I think he's outstanding, has no fear. For such a young boy he's got great awareness and his knowledge of the game is really good. I think he can be a big plus for us in this World Cup."
Johnson believes Sterling not featuring much in the recent friendlies might actually work to England's advantage when the action gets under way in Brazil.
"It would be ideal if people don't really know what Raheem is capable of and underestimate him," said Johnson. "That would definitely work in our favour. Hopefully people will underestimate him and then he can prove them wrong.
"He was on fire in training on Friday and he looks like he has been around the squad for years. When he gets on the ball you can see he has learnt the game quickly and he can hurt teams. He's probably the quickest in the squad over 10 yards.
"He has looked good all year. He's a young kid who is willing to learn about the game and he should just get better."