The 24-year-old singer-songwriter starred alongside Cheryl - who was serving as a judge - and Liam on the UK version of 'The X Factor' in 2010, and Cher has admitted she never saw their romance coming.
Appearing on ITV's 'Lorraine', she confessed: ''I never would have guessed it, but they look so cute together and they make a really great couple.''
Cheryl mentored Cher on the show, but the duo have not spoken for a ''long time''.
Despite this, Cher doesn't harbour any bitterness towards Cheryl because she appreciates that the former Girls Aloud star is currently busy raising her 11-month-old son Bear, who she has with Liam.
She shared: ''I haven't heard from her in a long time. I mean, she's so busy with her baby.''
In January, Cher announced that she's also expecting her first baby with her husband Phil Monk, having taken time away from the spotlight in recent years to focus on her music and personal life.
She wrote on her Instagram account: ''I decided to take some time away from the public eye to focus on what really matters and get back to what I truly love doing. As you all know, making music and singing is where it all began for me, it's what makes me truly happy, and I wanted to get back to that happy place once again, enter the studio and focus on simply making great music for you all. (sic)''
The singer - whose last album, 'Sorry I'm Late', was released in 2014 - then shared her baby joy and confirmed she's expecting to give birth in May.
The message continued: ''I'm so happy to announce that I now have a collection of amazing new songs (that I cannot wait to share with you all!), but also, there's another reason why I'm writing to you today and that's because I am beyond thrilled to inform you all that my husband Craig and I are also expecting our first child in May!!! (sic)''