"So excited to tell you all.............. I became someone's fiancé last night!" she tweeted. "I'm engaged to be married :)".
Katie has daughter Belle with James
It is thought that Katie's carpenter partner James, with whom she has daughter Belle, popped the question during a romantic homecooked meal as the acid attack survivor had been praising his culinary efforts on social media on Friday evening.
"Pretending we are going out for dinner!" posted Katie with a picture of herself laying the table, complete with a bottle of champagne on ice. "Cooking 3 course meal, dressed in our best clothes- all taking place at our kitchen table! Parents night in/out #nobabysitterneeded.
"I think my boyfriend has potential as a chef! Baked Cod with Capers," she added on Instagram, with a photo of her plate of food.
Katie, 31, introduced her baby daughter exclusively to HELLO! in March.
"People used to say to me, 'It's a love like no other,' and I understand that now," she told the magazine. "She's so precious and I just feel so incredibly blessed to have her. She's our world.
"To meet and fall in love with James," she added. "A man I knew I wanted to have a baby with and who makes me so happy, and now to have Belle – it's just amazing. Most of all I want her to be happy. I thought I knew, after all that happened to me, what happiness meant, but having Belle has shown me what true fulfilment is."