The Essex singer was chosen tonight by Will.i.am as one of his three finalists for the live finals, which begin next Saturday night.
"Who amazed me, who I think should be out right now with records and videos and touring is the person I'm putting through and that is Lydia," Will said when making his decision.
Lydia, who had performed Taylor Swift's I Knew You Were Trouble, reacted: "I can't believe it, honestly, I'm overwhelmed, I'm so thankful, thank you Will."
Lydia made it through to bootcamp on The X Factor back in 2013 but was controversially sent home ahead of judges' houses.
Speaking to Star magazine recently, Lydia compared her time on The Voice to The X Factor.
"The Voice UK has has given me the chance to be an artist, rather than just someone singing songs. It's given me more space to be me," she explained.
An ambitious Lydia went on: "I want to be successful in music. I want to reach the top and I'm not going up to give hip until I get there.
"The music industry is always a struggle. There are knockbacks and, if you can't push through them, you're not a strong enough person to be here. Having a big knockback on The X Factor just made me stronger."
Joining Lydia on Team Will are Lyrickal and Lauren Lapsley-Browne.
The Voice UK live shows begin Saturday evening at 7PM on BBC One.