Error adding object to mutable array

for (NSString *CurrentArtistName in ArtistNamesArray) {
    CurrentArtistName = [CurrentArtistName stringByMatching:regEx capture:1];
    NSLog(CurrentArtistName);
    [ArtistNames addObject: CurrentArtistName];
}

why is this closing my app ?

There are no errors in the cod开发者_C百科ing and the NSLog is logging the CurrentArtistName ? i really cannot understand why ?

Please help

Thanks

array = [[NSMutableArray alloc] init];    

I forgot to initialize the array XD

Noobie mistake but i thought i did