Pop star MELANIE CHISHOLM has threatened to quit the SPICE GIRLS - if her bandmates behave outrageously on their forthcoming world tour. The singer - who has previously dubbed herself 'Reluctant Spice' because she was the last to agree to a reunion - is keen to avoid the tantrums and tour demands the girls are already rumoured to be making. And the 33-year-old isn't afraid to quit the Wannabe group if the girls' behaviour gets out of hand. She says, "If it goes into a diva drama, I'm out of the circus." The reformed group will kick off their world tour on 2 December (07) in Vancouver, Canada.