The duo are raising money for the charity's campaign to help prevent women around the world dying in childbirth.
Bruton said: "Marianne and I are both mums and we were totally shocked when Amnesty told us that one woman dies every minute, mainly due to preventable causes in pregnancy. And of course it's women in the poorest countries who are most affected.
"We decided that we had to do something about it - and we hope that our friends, colleagues and Grazia readers will dig deep to help fund Amnesty's
Jones said: "This is my first marathon and I know it's going to be hard work. But it's a real inspiration to know that we're running for such a great cause, and one that I'm sure our readers will get right behind."