Liam Payne's girlfriend Kate Cassidy is remembering "the love of [her] life" in a heartbreaking tribute to the late singer following his tragic death.

The influencer penned an emotional message to her boyfriend in a post to her Instagram alongside several photos of the pair of them throughout their relationship looking happy and in love. Her post comes days after her initial public reaction to her boyfriend's sudden death at the age of 31.

"My heart is shattered in ways I can't put into words. I wish you could see the huge impact you've had on the world, even as it feels so dark right now. You brought so much happiness and positivity to everyone — millions of fans, your family, friends, and especially me. You are so incredibly loved," she wrote. "You are — because I can't say were — my best friend, the love of my life, and everyone you touched felt just as special as I did. Your energy was contagious, lighting up every room you walked into."

"None of this feels real, and I can't wrap my head around this new reality of not having you here," she said. "I'm struggling to figure out how to live in a world without you by my side. Together, we got to be kids again, always finding joy in the smallest things."

Cassidy, who has been linked to the "Strip the Down" singer since 2022, mourned the loss of her boyfriend with the "kindest soul and the most fun-loving spirit" and the future they had planned together, sharing that she feels like she "lost the best part of myself."

"I can't imagine a day without your laughter and love. You brought so much light into my life," she said. "A few weeks ago, we sat outside on a beautiful evening manifesting our lives together. I keep your note close, even though you told me not to look at it. It said, 'Me and Kate to marry within a year/engaged & together forever 444.' Liam, I know we'll be together forever, but not in the way we had planned. You'll always be with me. I've gained a guardian angel."

She concluded her heartfelt post with their angel number 444, telling Payne that she will love him for the rest of her life "and beyond" and will "[carry] our dreams and memories with me everywhere I go."

Payne passed away October 16 after falling multiple stories from his hotel balcony in Buenos Aires, Argentina. A preliminary autopsy report showed he died from the severe injuries he sustained in the fall, while a new toxicology report found that the former One Direction singer had a drug cocktail in his system at the time of his death called "pink cocaine," which included crack, cocaine and the Argentinian version of methamphetamine called "Cristal."

Read Cassidy's full statement in the post below.