Skylar Davies, 19, from Wollongong, died suddenly on Thursday after her heart stopped beating.
The teen had spent Christmas with her family after returning from university in Sydney when she collapsed with no warning while shopping at the Boxing Day sales.
Eilish, 18, mourned the teenager’s loss on her Instagram Story, sharing three black and white pictures of their photo together.
The singer later shared a sweet message above a photo of her hugging Davies that read: “Sending every ounce of love I have to Skylar’s family and friends. My heart is shattered.”
Skylar was a big fan of the singer, and had posted photos of them meeting at her concert in Hordern Pavilion on April 30.
“Last night I met the love of my life & I am forever grateful,” Skylar wrote.
Skylar had fans of her own, with a staggering 44,000 followers on Instagram. Her last post on December 9 now has more than 40,000 likes and 10,000 comments. Many fans have expressed their sadness at the news of her sudden death.
“Rest in peace angel,” one wrote. “You deserved the whole wide world. Fly high angel,” another said.
The teen’s father Rob Davies said she had just finished a five-hour shift and was shopping for shoes with a friend while waiting for her mother Leigh to pick her up, when she collapsed and went into cardiac arrest.
“Each morning we struggle to wake up and not feel emotional. I miss seeing her bed head, I miss her smell, I miss her smile I miss her so much,” he said on Facebook. “I feel her presence in her room, there is a plate from her breakfast that morning still on the bed. It’s a roller coaster of grief and we are just doing our best to support each other and get through each day.”
He said his daughter was a “genuine and kind soul … who touched many with her beautiful nature and creative talent”.
Skylar’s mother Leigh said it was “excruciatingly painful” coming to terms with her daughter’s death.
The family has launched a GoFundMe page to help cover funeral costs. It has so far raised nearly $6000.
“There are no words to express our grief. We lost our beautiful Skylar who passed suddenly yesterday with no warning,” the page reads. “Skylar collapsed, her heart stopped beating and she never regained consciousness. Skylar was our world and we are deeply heartbroken.
“Skylar was a genuine and kind soul, who touched many with her beautiful nature and creative talent. We really can’t believe she is gone.
“Our hearts break more each day as the reality that Skylar isn’t coming back sinks in. It’s hard to believe that beautiful heart just stopped, when she still had so much life to live.”
The page goes on to describe how Skylar had her whole life ahead of her.
“A true circle of friends, finishing your first year of a university course you always wanted and preparing for the next chapter in your life,” it reads.
“It’s times like this that make you question so much and why things happen the way they do. You gave us 19 years of joy our beautiful baby girl.”