An acoustic demo of 'Holding The Light' can be downloaded from The Voice UK star's website, where fans can also make a voluntary donation to Marie Curie Cancer Care.
Bruce's mother Rosamond Winkley died of pancreatic cancer just last month.
"I cannot thank you enough for your love, encouragement and belief over the last few months," Bruce said. "I couldn't have gotten through all this without hearing your words, your thoughts and your prayers. Thank you, thank you, thank you.
"As a tiny gesture of that thanks, here is a free download and video of 'Holding The Light' - written, recorded and filmed just before taking on the ride that was The Voice UK. I hope you enjoy it. This is the very least I can do.
© BBC/Wal to Wall/Guy Levy
"I am so excited about my album and can't wait for you to hear it - I'm working 24/7 and being held together by the greatest of souls, new friends and old friends that I hope will be around for a long, long time. You are all part of that."
Bruce will play London's Upstairs at The Garage on August 16 ahead of her slots at V Festival on August 18 (Hylands Park) and 19 (Weston Park).
