What is the title of this movie?

I've seen this movie before but I forgot the title! Please help me, I've been thinking about the title for quite some time already, it's bugging me. So here it goes. It's sort of like a rock star movie. Like a 30-year old guy was this former rocker dude then he meets these teenagers and helps them form a band. The scene I remember most was when they were contemplating on whether to play or not at some gig and the 30-year old guy says something like "Did you think the beatles asked their parents? Like hey mommy, can I go play with my chums **something something** AND RULE THE WORLD?". I think he said that line with a British Accent. I forgot who the actors were. This is all I remember. Hope someone could help me. :))