The 22-year-old Rixton singer shared a pic on Instagram of the moment he got down on one knee and popped the question to Jesy on stage at the Manchester Arena as the 'Thinking Out Loud' singer plays a song in the background.
Jake wrote: “A year ago today I met her at Manchester arena, so it was only right, with a little help from my friend, that this happened. Best day of my life.”
Following the news, Jesy shared her shock and joy at the proposal with fans on Twitter.
“I cannot believe what has just happened! The most surreal moment of my life and everyone that I love most was there to share it with us!” she gushed.
“I feel like the luckiest girl in the world rite now literally cannot stop crying!,” she added.
Jesy later admitted that the surprise engagement felt like winning the X Factor.
"I said to the girls, it was weird but it felt like when we won 'The X Factor', I felt like I wasn't there, it was really strange," she told KEY 103's Summer Live.
"It was all a bit of a blur, we were walking off cos I thought we'd finished soundchecking and then lo and behold, Ed walked out.
The girls were like, 'Jess, Jess' and I turned round and he sang mine and Jake's song - 'Tenerife Sea' - and as soon as he sung that I just knew, I balled.
"It was all a bit of a blur, I couldn't take it all in."
It’s been quite a week for 23-year-old Jesy. As well as getting engaged, Little Mix also scored their third No.1 single after their latest release ‘Black Magic’ topped the UK chart.
Jesy is the second member of Little Mix to get engaged, after Perrie Edwards' engagement to former One Direction star Zayn Malik in 2013.
Jake and Jesy first went public with their romance in September 2014.
Huge congrats to them both!