The 18-year-old, who has played Kelly Neelan in the soap for four years, is quitting the cobbles to pursue other roles, and her dramatic exit is set to air very soon, as Kelly sets out to destroy Gary after she learns he was responsible for her dad's death.
Georgie's character Toyah is involved in her own riveting plot, after she confessed to undercover cop Spider to killing her husband Imran, after he had an affair.
She wrote: "Last scene with my love aired tonight... @realgeorgiataylor," followed by a teary face emoji and a heart emoji.
Georgia, 42, shared Millie's post on her own InstaStory, writing: "Love you @milliegibbo", followed by a purple heart emoji.
Millie said: “Because I’m so young I thought I’ve got to leave.
"I have no responsibilities - I don’t have kids, I don’t have a mortgage to pay or anything like that, I’m still grateful to be living at home."
It seems the teen's parents weren't happy about her decision to leave, but she won them round in the end.
“When I first thought this is going to be the year where I do it, my mum and dad were like, ‘Are you sure? It’s such a secure place, you’re doing great, you’re having great storylines,' Millie said.
“And I was like, ‘I know, but I’ve got to trust my gut, I’ve got to trust my instincts.’
“I went with it without them even being on board with it at first but as soon as I started to go with it I convinced them."
Millie has been at the centre of some big storylines during her time in Coronation Street.
Her character was involved in a hate crime storyline that saw her charged with Seb Franklin's (Harry Visinoni) murder.
She was convicted of the murder before being acquitted of the crime after new evidence emerged.
Millie revealed she was a "wreck" as she filmed her final scenes.
While details are being kept under wraps, Millie told The Mirror and other press that her last moments on the cobbles are "emotional", with her bursting into tears during filming.
The actress previously took to Instagram to pay tribute to her co-stars with a gushing caption.
Alongside photos of all of her Corrie pals together, Millie penned: "Now that the news is out about me exiting the cobbles, I just want to say I've had the most incredible 4 years.
"Growing up here, I've made long lasting friendships, learnt so much and I am forever grateful for my time and the storylines I have been given."