Inside 5SOS' Luke Hemmings And Sierra Deaton's Surprise Announcement

There are wedding bells in Luke Hemmings and Sierra Deaton's future!

5 Seconds of Summer's lead vocalist Luke Hemmings took to Instagram on June 8 to announce that he proposed to longtime girlfriend Sierra Deaton (who he calls by her middle name, Thao) earlier in 2021. "With shaking hands but a full heart I proposed to my best friend earlier this year. I love you Thao and I can't imagine my life without you," he wrote alongside a slideshow of loved-up photos that showed off his fianceƩ's teardrop-shaped engagement ring. Deaton, who won "The X Factor US" in 2013 and rose to fame in the duo Alex & Sierra with her ex boyfriend Alex Kinsey, also shared the photos and wrote, "it was fun keeping this a secret for so long, but my heart is nearly bursting at the seams. can't wait for forever."

The couple has been Instagram official since July 2018 and aren't shy about expressing their love for each other. In a sweet post to Instagram in February 2019, Hemmings told Deaton that she makes him "the happiest ever." He also expressed that he hopes she "stick[s] around" for a long time. Now, it looks like she's sticking with him for life.

Deaton, too, was never shy of professing her love for the singer on social media, and even may have hinted that she was ready to spend the rest of her life with him a while back. Keep scrolling to read the smitten thing she wrote.

Sierra Deaton once said something huge about Luke Hemmings

While their engagement announcement was a happy surprise for fans, Sierra Deaton seemed to know she wanted to marry Luke Hemmings two years before he popped the question. In an adorable birthday post shared to Instagram in July 2019, Deaton called Hemmings her "best friend" and "soul mate."

"There aren't enough words to articulate how much i love every ounce of the being you are. lu, thank you for being my rock through hell or high water, but mostly for telling me everything i cook is the greatest thing you've ever tasted lmao. happy birthday to my very best friend. my soul mate. i love you forever," she gushed.

In June 2020 (via Daily Mail), Hemmings showed his support for his fianceƩ by wishing her a happy Pride Month because she is bisexual. "There is still so much work to be done but wanted to wish everyone a happy pride," he wrote on his Instagram Story. "Especially to my beautiful bisexual biracial angel." Earlier that year, a song that the couple penned together, "Lover of Mine," debuted on 5 Seconds of Summer's fourth studio album, "Calm," according to Apple Music.

It's clear Hemmings and Deaton are madly in love and supportive of one another, and now they get to celebrate their love for life. Congratulations to the bride and groom-to-be!