Jenna Coleman is "running out of noises" for her childbirth scenes in "Victoria".
The 32-year-old actress recently reprised her role as Queen Victoria on the ITV drama - which explores the monarch's 63-year reign, including the birth of her nine children - for a third season, and admitted that after having six on-screen kids she's "losing the variation of births".
Speaking on BBC Radio 2, she said: "I'm running out of noises now. I've given so many births I'm losing the variation of births.
"I'm like, "What else can I do?" And then I know one day I'll actually have birth and then I'll realise, "Ah OK, now I know, now I know what to do." "
The former "Emmerdale" star has a "selection of pregnancy bumps" for acting in the show, and jokes her character is "waddling round the palace".
When asked what fans can expect from the latest season of "Victoria", she said: "Probably the biggest pregnancy bump television has ever seen.
"I have a selection [of pregnancy bumps] we've got a selection we have foam, we have prosthetic but given this is Victoria's sixth child at the time so I'm waddling round the palace."
Jenna admitted she will eventually have to pass the "regal baton on" because it's becoming more difficult to portray the aging royal, compared to the inevitable recasting when Olivia Colman replaced Claire Foy as Queen Elizabeth II in Netflix period drama "The Crown".
She said: "I think there will be a point where we have to recast Victoria because, you know, I have seven children now, number eight is on its way.
"When else do I get to take a character to her mid-40s? But practically speaking there's definitely going to be a cut-off point.
"Yes there are great prosthetics but I'm lowering my voice so much at the moment, there's going to be a point where it's no longer feasible so I'm going to have to pass on the regal baton on."