One more week left to push 'Smile' to top spot

The 37-year-old's cover of 'Smile' has now slipped outside the top 50 having peaked at 16 after its release on Friday.

She is currently placed at number 63, with this expected to rise again with a week of press coverage across the UK.

Katherine tweeted that iTunes had said they were amazed at the number of downloads considering she's not on a major record label and hasn't benefited from significant marketing.

The song is being used to raise awareness of new cancer treatments; Katherine has a terminal form of the disease.

Smile is available to download from iTunes and costs just 69p.