At one point doctors told the 24-year-old, who played Robbie Flynn in the Channel 4 teenage soap Hollyoaks, that without treatment he could die within a year.
The actor, who has also appeared in Coronation Street and Casualty, has blamed the pressure of having to look good for his career for using sunbeds between one and five times a month for years.
And now he wants to warn other young people about the dangers.
He said: "I really want to say don't use sunbeds: it's really not worth it.
"I hope it will make impressionable 17 and 18-year-olds think twice: it is about time someone spoke out."
"I know people who go on sunbeds every day and I was never one of those. It was just to look sort of healthy which is quite ironic."
Mr Newton-Lee, who lives on the Kingswood estate in Hull, has had five procedures, including two operations to remove cancerous cells from his legs, since being diagnosed with malignant melanoma – the deadliest type of skin cancer – in August. He will hear tomorrow whether the latest operation has been a success.
Yesterday he told the Yorkshire Post how he began to suspect something was wrong last Christmas when he noticed a brown mark on his left leg.
He said: "It wasn't a mole, but a brown growth which had come from nowhere. I got it checked out twice but they said there was nothing wrong, but I insisted they refer me to a dermatologist."
A biopsy revealed it was a malignant melanoma, which had to be removed by a plastic surgeon during a two-hour operation, leaving him with a 6in by 4in scar.
However, a second growth appeared on his right leg, which also turned out to be cancerous.
He initially failed to grasp how serious the situation was, but the moment of truth came on holiday with friends.
Mr Newton-Lee said: "I went on a lad's weekend to Majorca in July and it all kicked off. It went black and I thought 'this is scary'. I came home and got it removed.
"Initially I kept it to myself, family and a few friends, but then a few people started asking what was up with me. "People have been really good. Skin cancer is the most treatable of of them all, but it gets tricky when it starts to spread. I was on the table for two hours when they removed my first growth. It was traumatic.
"Doctors then discovered another one on my right leg and that was also malignant melanoma. I was told if they didn't treat it then, I'd be dead in nine months to a year," he added.
"The doctor told me my type of cancer can quickly travel up lymph nodes to your groin and pancreas. I thought, 'This is crazy. I'm only 24'."
Around 7,300 people are diagnosed with malignant melanoma each year in the UK. Of those, 1,700 die. The main cause of malignant melanoma is ultraviolet rays from the sun.
Research has shown that the use of sunbeds – which give off artificial ultraviolet radiation – increases the risk of developing malignant melanoma, even when only used occasionally.
Despite the diagnosis, he also revealed he is moving to California in an attempt to break into the American TV and film industry in January.
"I have an agent and I want to relocate. I got a really positive response when I was in LA.
"This has re-affirmed the way I live my life. I live for the day with an element of responsibility.
"I am an ordinary lad from Hull, from a council estate. My dream was to be in Hollyoaks when I was younger and I now want to be in one of the American shows, like Nip Tuck, which I love, or Desperate Housewives."
Mr Newton-Lee, who has also had a biopsy for a mole on his stomach, is now in talks with Cancer Research UK to be the face of their SunSmart campaign next year, which will advise people not to use tanning beds.
Although doctors cannot prove the cause of a cancer, he was said to be in the lowest risk group as there is no family history of skin cancer.
He said: "If what's happened to me stops someone else from getting skin cancer then at least something good has come from it."
alex.wood@ypn.co.uk