The 89-year-old said his condition was "mild" and that the cancer is very treatable.
Here is some more information on the illness:
What is the lymphatic system?
The lymphatic system is one of the body's natural defences against infection and also acts as a one-way drainage system transporting fluid from body tissues into the blood circulation.
The system is made up of lymph nodes which are found mainly in the neck, armpits, groin and abdomen.
What is Lymphoma?
Lymphoma is a cancer which starts in cells, the lymph nodes, and other tissues of the lymphatic system.
There are two types of cancer which can start in the lymph nodes - Hodgkin lymphoma and Non-Hodgkin lymphoma.
What are the differences between the two?
The main difference between the two is the presence of a specific type of abnormal cell called a Reed Sternberg cell in Hodgkin's lymphoma.
The distinction is important as the outcomes and treatment for each type can be very different.
More top news
A wet end to the month with a deluge of rain across much of southern Britain.
The most shocking finding is that 75 of 95 buildings found to have failed cladding fire safety standards were Category 3 failures.
Judges in the European Court of Human Rights have rejected a plea from the parents of terminally-ill baby Charlie Gard to intervene.