Willow Jessica Phillips from Sutton is having her long blonde hair cut off to raise money and is donating her hair to the Little Princess Trust.
The charity uses human hair to make wigs for children who have lost their own hair, often due to cancer treatments.
Mr Anderson said, today (Thursday): “I am sure a mention from the Leader of the House will go a long way to help her increase her £600 already raised to help other little girls throughout the UK.”
Jacob Rees Mogg said: “What a wonderful little girl Willow sounds, for what she is doing for the Little Princess Trust, a truly moving cause supporting young children suffering cancer, I commend them for their work.
"Willow’s efforts are particularly impressive, raising £500, a terrific achievement. I wish her all the luck in the world in her fundraising.”
The St Mary’s School pupil launched her appeal two weeks ago, backed by her mum Charlotte, dad David and big sister Kara, 13.
David said: “She’d been saying she wanted to cut her hair to help other little girls for ages, we thought it was just a phase and said we’d sort it after our holiday to Florida in November. But the minute we got back on November 21, she held us to it!
“We hadn’t really pushed it, it was mainly friends and family donating. I messaged Lee to tell him about it, we never expected this! It’s amazing!
"We couldn’t be prouder of our daughter. For a five-year-old wanting to do this off he own bat, it’s a special thing.”
Dozens took to Mr Anderson’s Facebook page where he posted a video of him raising the matter in Parliament.
She will be having her hair cut at Elle-K’s hair design, in Sutton, at 1pm, on SaturdayDavid added: “One wig costs about £550, she has done that already.”
To donate click Willow's Just Giving appeal.