Megan Mullally has promised that the eagerly anticipated Karen: The Musical will be over the top.

The American singer-actress plans to reprise her Will And Grace role as feisty Karen Walker for a Broadway musical focused on the character's antics, which she is writing and composing.

"The whole thing was my idea - I think the point is to make it just as absolutely ridiculous as possible, just to make it the stupidest thing you've ever seen, and then I would be very happy, yeah," she said.

"The idea of Karen unbridled without any censorship, just the idea of Karen singing, I think is ridiculous and must be done. It would only be done as pure amusement and if it's not funny enough, I won't do it," she added.

Megan - who's performing at London's Vaudeville Theatre with her band Supreme Music Program - is looking to bring Leslie Jordan back as Beverley Leslie.

"It's going to be Karen and Beverley Leslie, her arch-nemesis. The two of them together, in a bitter fight to the death," she added.

:: Megan Mullally And Supreme Music Program are performing at London's Vaudeville Theatre until February 21.