Thousands of young Calgarians are expected to rock out Saturday at a giant Christian concert.

Rock the River, at Canada Olympic Park, is a touring show that attracted 70,000 fans at a recent stop in the United States.

Franklin Graham, in front of a portrait of his father, Billy Graham, is bringing his evangelical Christian rock show to Calgary on Saturday. (Chuck Burton/Associated Press)The man behind the show is Franklin Graham, a controversial American evangelical preacher who has made headlines for his anti-Muslim commentary.

Between sets, Graham, the son of famed evangelist Billy Graham, will preach and then invite members of the audience to come to the stage and become Christians.

Morgan Lock, 15, is among the approximately 300 volunteers who will be at the stage to accept those who come forward.

Lock said this concert is all about her favourite rock music — "It's just going to be so cool" — but she has another reason to take part: Lock's parents bought tickets for eight of her non-Christian friends, friends who Lock said have tried pot and been drunk.

"You can definitely tell that they need something more but they are not exactly sure what that is," Lock said, adding she thinks that something is religion.

She told CBC News it can be hard to be a teenager who likes Christian music.

"Like, I don't go sharing my iPod with everyone because I know a lot of them would be a bit offended if I did. But at the same time I really like my music, so I'm not willing to give it up."

Unlike Lock, volunteer Dylan Hunt, 16, hasn't invited any of his non-Christian friends to come along.

"Why not? I just haven't gotten up the nerve and, I don't know, I could really work on that," Hunt said.

The show will travel to Edmonton next weekend.