What made you want to appear in Chicago?
"Well, the musical itself is obviously legendary and I'd have been a fool not to attach myself to it. Also, I felt it was time for me to get back on that theatre stage. In between each album I want to take on some kind of theatre project and I seem to be managing it so far."
How are rehearsals going?
"Well, I'm really having fun identifying who Roxie is, though it's taken me a while! It's just been this past day that I've really been able to get my head around her spirit. I've actually realised that the character of Roxie has a lot of similarities to my grandmother. My grandmother was born in 1920, so she was actually alive in Roxie's era, and like Roxie she ran away and eloped. You know, my grandmother got married in a courthouse and never even had a reception."
Is it hard getting into the mindset of a murderer?
"You know, I haven't even thought of it that way! I guess I'll have to think about it at rehearsal today and then call you back to let you know! So far I haven't really looked at Roxie as a murderer to be honest. She just seems really sweet to me, though at the same time she can be really mean and manipulative."
Last year you released Unexpected, your first pop album as a solo artist. Were you pleased with how it was received?
"Of course I wanted better sales and to be able to tour, but I was pleased with the reception it got considering it was my very first mainstream pop album. I'm kinda known as a gospel girl, so I think I have to push a little harder to make people believe I can also do pop music. I think the album did well at getting that message across."
Were you disappointed that 'We Break The Dawn' - the frankly fantastic lead single - didn't become a bigger hit?
"I'm going to be honest with you, I was disappointed. I worked with some great producers on that song, as I did with all the songs on the album. I really feel my album was able to stand with all the other pop albums that came out in 2008. Like I said, this was my first one and I just have to keep going to prove I can do this kind of music."
Are there any plans for an album reissue?
"I've been told that's the plan by the folks here at Sony in London. If so, I'm very excited about that! There's a possibility that I might record some new tracks for the reissue. I also have a remix album that's completely done, so I might be able to put some of those tracks on there. The remixes have a lot of real instruments on them and they offer a jazzy, hip-hoppish take on some of the songs from the album."
Have you had a chance to hang out with Kelly since she reached number one with 'When Love Takes Over'?
"I know, I'm so excited for her! We actually celebrated together the other night. We had dinner at Nobu and then we went on to a club called Mo*vida. Normally when we go out we're very reserved, but every now and then we'll get up for a shimmy."
Are you keen to record a big dance song like 'When Love Takes Over'?
"Actually, I just did a big dance song with Ultra Naté. We sing it as a duet and it's called 'I'm Waiting On You'. They're doing the final revisions on it at the moment and I'm very, very excited about it. I think it's for her record, but it's a big track so of course I'll put it on mine too."
Finally, there's a rumour going round that Destiny's Child are contractually obliged to reform for one last album. Is there any truth to this?
"You know, I honestly don't know. Is there anybody from Sony on the line to help me out? I'm not giving you the answer I've been told to give or anything, but to my understanding I'm not obligated. Would I be up for a reunion? Oh definitely, but one day in the future when everybody's ready to do the group thing again."
Michelle Williams stars in Chicago at London's Cambridge Theatre from July 13 to August 23.