Paul Ritter, a British actor best known to American audiences for his roles in HBO’s “Chernobyl” and “Harry Potter and the Half-Blood Prince,” has died of a brain tumor. He was 54.

Representatives for Ritter, whose other notable credits include starring on U.K. series “Friday Night Dinner” and appearing in the James Bond film “Quantum of Solace,” confirmed his death to TheWrap Tuesday.

“It is with great sadness we can confirm that Paul Ritter passed away last night,” Ritter’s agent said in a statement. “He died peacefully at home with his wife Polly and sons Frank and Noah by his side. He was 54 and had been suffering from a brain tumor. Paul was an exceptionally talented actor playing an enormous variety of roles on stage and screen with extraordinary skill. He was fiercely intelligent, kind and very funny. We will miss him greatly.”

“We are so saddened to...