Renee Zellweger has told Sky News she is her own worst critic, saying she feels a responsibility not to let others down when making her films.
The Hollywood star is best known for playing Bridget Jones, but has also won an Oscar, a BAFTA and several Golden Globe awards for her roles in films such as Cold Mountain, Nurse Betty and Chicago.
Now, after a few years out of the spotlight, she has transformed herself once again for her latest role as Judy Garland, which is already being tipped for awards in 2020.
But after a career spanning more than 25 years, Zellweger says she still worries about making mistakes.
“I know I can be my own toughest critic because if I didn’t do something right you don’t have to tell me, I already know,” she says.
“I knew before I finished the thing what I did wrong and could have done better, and that’s probably genetic and upbringing – my Swiss engineer father, you know. I am my Swiss engineer father’s daughter.”
Zellweger sings some big numbers in Judy, including the Garland classic Somewhere Over The Rainbow.
She says she had to silence the critics in her head while tackling the role.
“I think when you go into any experience, for me I’m not thinking about what’s going to come of it… I’m worried about what the director’s going to think, what my co-stars and partners are going to think – it’s a collaborative medium,” she says.
“There’s a couple of hundred of us who are participating in making this one piece of art, and I just want to hold up my end.
“Especially when you’re involved in something that is meant to be a celebration of someone who is as extraordinary as Judy, you just feel a responsibility to not forget anything or leave something out, you just want to get it right.”
The film focuses on a period of time towards the end of Garland’s life, when she came to London to play a series of shows.
There are also flashbacks to her younger self and the way she was treated by the studio that should have been protecting her.
Young Judy is refused food and given pills to ward off hunger and help her sleep.
Rufus Sewell, who plays her ex-husband Sidney Luft in the film, says it was a dark time.
“At the time when Judy Garland was doing the Wizard Of Oz you think of that as being the most innocent time, but the expression of that innocence comes at the expense of all of the people involved,” he says.
“It was a very, very abusive time, and so all of that that was malignant about humanity was pushed under the surface with no light on it, and it thrived.
“I think the situation now, where there’s less shame involved in talking about these things, including mental health issues, abuse – the more light that’s shone on these things the more healthy we can be, so I like to think it’s getting better.”
Zellweger says the situation in Hollywood is improving.
“Well it’s inevitable, isn’t it? I mean, the younger generations of women are coming of age and women of my generation have agency now.
“We participate in decisions that are made about the trajectory of our careers and we make choices and there’s less ignorance about the consequences of certain choices that we make.”
Despite the awards buzz around Judy, Zellweger says that was not in her mind when she decided to take the role.
“It’s really kind but the treasure is in getting to participate in it and make it,” she says.
“It’s a miracle when any film gets made, and when you get to have an experience like this one, that is such a life blessing and that it had its importance in something else, and there’s celebration and this acknowledgement of her importance, not just in pop culture history but in history – that’s the blessing, isn’t it?”
Judy is out in cinemas in the UK on Thursday