By Tom Bryant Louis Walsh last night revealed he has been fighting a rare form of blood cancer. The former X Factor judge was diagnosed with waldenstrom macroglobulinaemia. Speaking on Celebrity Big Brother, the 71-year-old star said he was recovering from a rare cancer, adding that it had been a “reality check”. Louis made the admission in a conversation with housemates Levi Roots and Ekin-Su. Asked about his experiences in lockdown, he replied: “I was sick, and I think nobody knew I was sick. I had cancer – a mild version, a rare one, in my blood. “I didn’t even know I had it until I went to…