The producers of the show have sued their insurer, Lloyd's of London, for refusing to cover the losses caused by the Tony winner's departure.

Pregnant MCDonald was forced to step down from the musical in July (16) and she was set to be replaced by Rhiannon Giddens, when producers pulled the plug on the production.

In a statement released at the time, producer Scott Rudin wrote: "It has become clear that the need for Audra to take a prolonged and unexpected hiatus from the show has determined the unfortunate inevitability of our running at a loss for significantly longer than the show can responsibly absorb.".

Forbes reports the show's bosses took out two multi-million dollar policies in case their leading lady fell ill and was unable to perform, but Lloyd's officials insist pregnancy is not covered under the terms of the agreement - and, as a result, they won't be paying out.

The insurance experts also argue the producers didn't have to close the show, adding, "Ms. MCDonald is also only one of a number of stars performing in the show. By virtue of the all-star cast, Ms. MCDonald's temporary absence does not appear fatal to the show's continued success."

The six-time Tony Award winner and her husband Will Swenson welcomed daughter Sally James on 19 October (16). The couple, who wed in 2012, announced the pregnancy in May (16).