Sessions studied at the Royal Academy of Dramatic Art, where he met fellow actor Kenneth Branagh, and the pair went on to work together for a number of shows.
Fans came to learn of his improv skills when he created the stage show Napoleon for the West End in London in the 80s.
His skills as an impressionist led him to voice some of the characters in the puppet sketch show, Spitting Image. He went on to star in countless other TV shows, more recently Outlander, The Rack Pack and Friday Night Dinner.
Many friends and fans continued to pay tribute to the star on Twitter, with one saying: “Shocked to hear that John Sessions has died at 67.
“Terrific company always and a true talent. His roles at the heart of this, my favourite radio series, have given endless pleasure to me and will continue to do so always. Travel easy, chum…”