Van Gaal, 70, said he had kept the news from his players during the recent international break.

"I didn't want to tell it to my players because it could have influenced their performances," he added.

Van Gaal is in his third spell as Netherlands head coach, having led them to third place at the 2014 World Cup and now to the 2022 finals in Qatar.

He added: "In each period during my time as manager of the national team I had to leave in the night to go to the hospital without the players finding it out until now. While thinking I was healthy, but.. I am not."

In a two-year spell at Manchester United, Van Gaal led them to FA Cup success in 2016 before he was replaced by Jose Mourinho.

He has also won league titles with Barcelona, Bayern Munich, AZ Alkmaar and Ajax, where he led the Dutch side to Champions League glory in 1995.

That triumph came just a year after Van Gaal's first wife, Fernanda Obbes, died after she was diagnosed with liver and pancreatic cancer.

Speaking in an interview to promote a new film about his life, Van Gaal added: "I've been through a lot with illnesses, including with my own wife. So that's just part of life.

"[I] as a human being have probably become richer because of all those experiences."

Van Gaal is due to be in charge of the Netherlands at the World Cup in Qatar in November, with his side in Group A along with Senegal, Ecuador and the hosts.

Last month he called the decision to hold the tournament in the Gulf country "ridiculous" and said world football governing body Fifa had been solely motivated by "money and commercial interests".