This brings a whole new meaning to foxhole friends: Siegfried Sassoon was good buddies with many famous literary figures, including Robert Graves and Wilfred Owen. (Source.)
Sassoon was a super brave soldier, but his comrades often thought he was a little nuts, so they nicknamed him Mad Jack. (Source.)
Mad Jack dedicated a volume of poetry, The Old Huntsman, to the great English novelist and poet Thomas Hardy, who, we should also point out, wrote a fair few poems about war.