Christina Perri's A Thousand Years set to return to the Official Singles Chart Top 40 after viral Carpool Karaoke video in support of World Down Syndrome Day

Fans have returned to the 2011 hit after it was used in a carpool karaoke-style clip in support of World Down Syndrome Day.

Christina Perri's touching ballad A Thousand Years could make a return to the Official Singles Chart Top 40 this week after it was used in a Carpool Karaoke-style video in support of World Down Syndrome Day.

The video, which has been watched 3.4 million times on YouTube, features 50 mums and their children singing along to Perri's 2011 hit. 

The mums are all part of a Facebook group known as "Designer Genes", created for parents who have a child with Down’s Syndrome born in 2013/2014. The video was inspired by Singing Hands - a UK organisation who's videos have helped many in the group learn Makaton for supporting their children’s communication development.

Reacting to the video, Christina tweeted: "THIS IS THE BEST!!!! i’m so honored they chose my song! my heart is so full!!!". A Thousand Years is at Number 39 in the latest sales flash, which you can check out in full here.

Discussing the video's accompanying hashtag #WouldntChangeAThing, Becky Carless, who came up with the idea, told This Morning: "We say we wouldn't change a thing about our children but we'd change the world for them. We want to put across a positive view on our lives and that we're all happy and our kids are all happy. The barriers that we cross tend to be people's perception of our children." 

Fellow mum Victoria added: "It's positive awareness... Down's Syndrome for new mums, it's to give them awareness that life is actually more normal than you'd ever believe."

Christina Perri's A Thousand Years peaked at Number 32 upon its original release in 2011. It re-entered at 13 the following year and reached its Number 11 peak in 2013 after being performed on various TV talent shows, including The X Factor. Look at Christina Perri's full Official Chart history, including A Thousand Years' week-by-week UK chart run, here.