The 99-year-old WWII veteran Captain initially wanted to raise £1,000 for NHS Charities Together by walking 100 lengths of his garden in Marston Moretaine, Beds, with the help of his zimmer frame, before his 100th birthday.
After Piers Morgan invited the war hero onto Good Morning Britain last week, his JustGiving page went viral on social media, and Tom soon racked up millions in donations.
Now, the TV host is supporting Captain Tom in the hopes he will be knighted for his tremendous efforts.
Speaking on today's GMB, before Captain Tom hit the £5 million mark, Piers said: "I've just launched a campaign on Twitter, as it's suddenly come to me.
"Wouldn't it be nice to see Captain Tom Moore, who served his country in World War Two and has now raised over £4 million for the NHS in a week, knighted for his service to to the country?
"He's 100 on April 30th. Wouldn't it be great if we didn't feel temptation to give it to business people, who pay money for the honour, or to celebrities for singing nice songs.
"But we give it to someone like him. That we make him Sir Tom. I think it will be great. If you're with me, let's get a campaign going and let's give him something back."
Since the show air, Piers took to Twitter, writing: "I’d like to see the magnificently inspiring Captain Tom Moore be knighted for his services to his country in WW2 & now to the NHS. Who’s with me?"
Piers has donated £10,000 to Tom's cause, and thousands across the UK have continued to add to the fund.
Captain Tom Moore, is aiming to walk a hundred lengths of the back garden – which is 25m in length – before he is 100 years old at the end of the month.
With the help of zimmer frame, he aims to complete the lengths in 10-lap stints each time.