The inspirational author and activist enjoyed a glamorous night out before booking in for her pre-scheduled throat surgery on Wednesday morning (22 April).
Katie looked beautiful as she walked the red carpet at Westfield White City on Tuesday evening clad in a white jumpsuit with lace top from Miss Milne.
The mum-of-one rubbed shoulders with Avengers stars including Scarlett Johnasson, Robert Downey Jr, Chris Hemsworth and Elizabeth Olsen at the star-studded premiere.
This morning, she was back in hospital for further surgery on her throat.
Katie shared an image of herself in a hospital gown to Instagram alongside the caption: "Back in hospital today for further surgery on the tears in my throat – reassuring sign on the wall!" The sign read: "Keep calm and stop worrying… You are in the safe hands of best professionals!"
Katie's had multiple surgeries since 2008 when an ex-boyfriend arranged for acid to be thrown in her face.