Brian Barwick, chairman of the Rugby Football League, told Charles: "The critical thing for Rugby League is that it is being talked about."
Sam Burgess, who is banned from England's next match after a high tackle against Australia's Sam Thaiday, was among the stars who met Charles at Clarence House.
Mr Burgess, who is originally from Yorkshire and enjoys a celebrity status in Australia, said: "People don't recognise me as much here as they do in Sydney, which is quite refreshing. I am enjoying being back in England and hearing the English accent."
Mr Burgess, who plays for England along with two of his brothers, said: "To stand and sing the national anthem arm in arm with my brothers was really special. It was a moment to remember and it made me very proud. England is home for me and that will always be the case."
Ben Flower, a rugby player for Wales, said he remains positive about Wales' chances in the World Cup, which is being co-hosted by England and Wales, despite losing in their opening game to Italy.
Mr Flowers said: "We will hopefully be moving on from last weekend. We have been doing video analysis about the different key areas we need to improve on. The match against the US will be a tough game. We want to win and we will do all we can."
Iestyn Harris, head coach for Wales, said: "Our priority is to win as many games as we can. We have a lot of work to do to get there. I want us to keep on improving so that by 2017 we have a bigger and stronger pool of players."
Andrew Henderson, who plays for Scotland, said he was excited about the match against Fiji.
"We have prepared really well for the match. We had a warm up game against Papua New Guinea which we lost, but we drew important lessons from it and we got a feel of what to expect tonight."
Nigel Wood, the world cup tournament director, said: "Everything is going wonderfully so far. It has exceeded all expectations. We want to raise the profile of Rugby League in England and Wales. Hosting the world cup has done a tremendous amount of good for this and it is a tremendous privilege to host it."