The pair joined forces to re-release Dame Lynn's famous wartime song in support of NHS workers and their families.
The song had seen a recent surge in popularity after the Queen made reference to it in her historic address to the nation on April 5.
All of the money raised from sales of the duet are going to NHS Charities Together.
The re-versioned song was released on Saturday 11 April and climbed the iTunes charts to reach number one just five days later where it bumped The Weekend from top spot.
Katherine Jenkins took to social media to thank everyone for their support and encouraged people to carry on downloading it.
The money raised from sales will go to NHS Charities Together. They represent charities helping NHS staff and volunteers.