The couple began dating in 2018.
Luke Hemmings and his girlfriend, Sierra Deaton, are taking the next step in their relationship.
On Tuesday, the 5 Seconds of Summer musician revealed that he had proposed to Deaton earlier this year, posting several snapshots of the special moment to his Instagram account.
"With shaking hands but a full heart I proposed to my best friend earlier this year", he wrote. "I love you Thao and I can't imagine my life without you ❤️ @sierradeaton."
In one shot, Hemmings is seen putting an enormous diamond ring on Deaton's finger as the pair smile and look into each other's eyes. In another, the couple share a kiss in front of a scenic mountain backdrop.
Deaton —who began dating Hemmings in 2018— also took to Instagram to share a loving message for her now-fiancée.
"It was fun keeping this a secret for so long, but my heart is nearly bursting at the seams. can't wait for forever �� @lukehemmings", she captioned a series of photos from the happy couple.