Millions of TV fans were left shocked and heartbroken after Poldark's baby tragically died in the finale of the hugely successful BBC drama on Sunday.
But what they didn't know is that the little girl who played the hero's daughter nearly died herself after she was born nine weeks prematurely, weighing just 2lb 12oz.
Matilda Fitt, who played baby Julia Poldark in the heartbreaking end to the series, battled to beat pneumonia to make her small screen debut.
Now 21 months old, Matilda was chosen for the part because of her small size. On TV Julia died from putrid throat in the emotional finale.
Matilda's mum Hannah Fitt, 34, revealed how it brought tears to her eyes because of her own daughter's fight for life.
She told her local paper: "It was very emotional seeing it because of what we've been through.
"Matilda was in and out of hospital for check ups and tests since birth. She had a lot of breathing difficulties and pneumonia.
"But last September she was finally discharged from hospital consultant care and a few weeks later she won the part of Julia."
Hannah took Matilda from her home in Barry, South Wales, for the filming in Cornwall last year to meet stars Aidan Turner and Eleanor Tomlinson.
She said: "The cast were all great with her and Aidan Turner is as lovely as everyone says.
"All the cast were - especially Eleanor. She's a very special person, extremely down to earth and just lovely - she was great with Matilda.
"Some scenes were tricky to nail because baby Julia is supposed to be really poorly and we knew Matilda did have to die on camera.
"As you can imagine getting a 15-month-old to play dead was no easy feat but she coped really well.
"In the scene she is lying on a bed fully made up and the doctor is mopping her brow. But I was there with sweets to make sure she was happy."
Millions saw the series finale as Ross and Demelza's baby daughter die of the terrible illness - sending viewers into shock.
The final episode saw the people of Trenwith become stricken with a disease after an outbreak of putrid throat.
Demelza went to their aid and then became infected herself, passing it on to baby Julia who tragically died.
Matilda, who lives with her mum and dad Matthew Fitt, 33, was cast as the older of two young children who played Julia.
Hannah - who works for the SAFE Foundation helping disadvantaged people - said: "It was only a few after she was released from hospital care that my sister-in-law saw the casting call for a baby girl.
"We decided to put her forward.
"Soon after she was accepted and we were only told minimal information - all I knew is that it was filming for a BBC production.
"We spent five days filming. Matilda was a bit of a diva occasionally but she always came around with some bribery of toys and books.
"She even had her own trailer and a rider of green grapes."But we want everyone to know that in real life Julie - or Matilda - is very well and doing fine. She is a little star."
The episode provoked a big reaction from fans on Twitter, with one viewer saying: "I'm currently in shock from the last episode of Poldark. And will likely continue to remain in shock for the rest of this week. Sorry world."
Another posted: "Oh my goodness how sad is this. Poor Ross, poor Demelza, poor baby Julia."