The ewe, which has since been nicknamed Swampy, had ventured into the mire to rescue a lamb when the British PM sprung into action.
The episode took place in Cameron’s rural Oxfordshire constituency.
The PM waded in, together with his two armed guards, and pushed the ewe to safety.
The farmer, Julian Tustian, said, “When I got there, David was in the swamp, waist-deep in mud, along with the two police, who had all gone in there to help drag this sheep out.”
The daring rescue was revealed when Cameron was asked what he would do after politics when he took questions from winners of the Mum of the Year awards at Number 10.
“Well, I helped my neighbour with his lambing one weekend and that gave me more pleasure than anything I’ve done for a long time,” he said.
He added, “We managed to get the ewe out. Some of the staff with me joined in. We all jumped in and were up to our waists in the swamp. So this ewe has now been named Swampy and she’s alive and well. I’m not saying I’m going to be a farmer, but I do love the countryside.”
Photos: Salman Khan returns from Jodhpur to Mumbai
Pics: Sidharth Shukla-Rashami Desai's sizzling chemistry at TV show launch
Ooh La Lana! WWE Diva flaunts sexy curves in these 30 pictures
15 'peach' perfect photos of Priyanka Chopra at People's Choice Awards 2017
62 going on 16: These photos of Rekha prove she is 'forever young'