Chicago is a hit in Sydney because it has the cynical, black humour that the city loves.  Chelsea Clark reports ... "Ladies and gentlemen, you are about to see a story of murder, greed, corruption, violence, exploitation, adultery and treachery -- all those things we hold near and dear to our hearts."     Not only does this opening raise the curtain on the razzle-dazzle musical Chicago each night, but according to the show's newest cast member Sharon Millerchip, it sums up all the reasons behind its success in the Olympic city.     "Chicago is full of that black, cynical humour that Sydneysiders seem to love so much," she said.  "The sexiness and sassy humour is particularly Sydney."     Millerchip is filling the void left by Caroline O'Connor, as the brazen, high-kicking murderer Velma Kelly.     It is a role for which O'Connor recieved five-star reviews, but Millerchip thinks she can live up to the high expectations, thanks to a bit of hard work and a few tips from the performer herself.     "Caroline and I are great mates and have been for years, so she did manage to pass on a few hints here and there," Millerchip said.     "Mainly tips on pacing myself through the course of the show because it's a bit of a marathon really," she said.     "The role is challenging on so many different levels but certainly the physical stamina is a big hurdle because you're performing the show eight times a week and sometimes twice a day.     "The audience doesn't want you to come out like a huffing and puffing, tired old thing.  There's an obligation to keep my performance really fresh and each time I do it, it has to look like the first time I've ever done it."     It's the second time Millerchip has replaced O'Connor in a musical -- the first, in 1995, was when she took on the role of Anita in West Side Story.     "I'm like a vulture, I just hover close by when Caroline leaves a show," Millerchip joked.     "In terms of skills we're both quite similar.  We both are singer/dancer/actress/comedienne types so I guess it makes sense that we would do the same kind of roles."     Although Millerchip has only been doing the Chicago role for one week the early reviews were favourable.     One reviewer wrote: "Her big opening number All That Jazz started almost whisper-low and sounded oh so sultry."     "It's been a baptism of fire," Millerchip said.     "I'm just happy to have that first week under my belt so I can now get on with the rest of the run."     And what about the inevitable comparisons with O'Connor?     "I hadn't really thought about that [the comparisons] until everyone started asking me if I was nervous about it," Millerchip said from her Capitol Theatre dressing room.     "She has certainly made it difficult by being so fantastic but the role is wonderfully written so you can really make it your own which is certainly what I am trying to do.  Velma is really a dream role because I get to squeeze every ounce out of everything I have plus I get to exploit all my talents in the course of the show."     Along with O'Connor's departure came goodbyes from John Diedrich and Anthony Weigh, who played lawyer Billy Flynn and Amos Hart respectively.     Diedrich was replaced by Australian theatre stalwart Simon Burke while comedian Glen Butcher moved into Weigh's role.     Millerchip said: "All three of us started together last week, we were like the new kids on the block.     It sounds really cliche but honestly, the rest of the cast have been absolutely fantastic."     "When we were rehearsing the show the rest of the cast were coming to work on their days off, after doing eight shows a week, just so we could rehearse with them and they never made us feel guilty about it."     Chicago has been showing at the Capitol since February but the run finishes at the end of this month.  The 1975 musical, by John Kander, Fred Ebb and Bob Fosse, has been playing to full houses since it opened after celebrated seasons in Melbourne and Adelaide.     Millerchip will stay with the show until, at least, next May, after stints in Perth, Brisbane and then to Hong Kong and Singapore.     "I love performing but I have a husband here in Sydney so it's not quite a perfect world," she said.