The Scots writer was proving his ‘new man’ credentials by helping to hang out his smalls out at his Edinburgh home on Saturday.
But just as he bent down to hang the last of his clothes, he felt his back go.
The award-winning novelist is now off to his doctors to help cure the excruciating pain.
Rankin has also expressed his reservations over the new Burke and Hare movie to be filmed in Edinburgh next year.
The Scots author could be seen visibly wincing while opening the new £2 million St Andrews University Museum on Tuesday
When asked to bend down and pose beside two life masks of the infamous grave robbers, Burke and Hare, by the assembled photo pack, the Fife-born writer complained of suffering back pain.
He later revealed his injury was caused by doing his domestic chores.
He said: “Yes, I’ve done my back in. Boringly, though, I did it by picking up some washing at home, nothing exciting at all.
“I’m planning on going to the doctor this week because the pain is almost unbearable.
“I just couldn’t bend down when the photographers asked me to.”
The best-selling crime author also revealed he hasn’t been asked to participate in the planned movie of the Burke and Hare story to be filmed in the capital early next year.
His novel The Falls is based on the 17 tiny wooden coffins found on an Edinburgh hillside which are rumoured to have been buried in memory of Burke and Hare’s victims.
But he did express doubts over the planned format of the film starring Trainspotting actor Ewan McGregor.
He said: “Like the majority of people I just read about it in the newspapers at the weekend.
“But I was interested in the fact they seem to be doing it as a comedy. One of the rumours about it is that will be comedic and I’m not really sure about that.
“But I will be fascinated to see what comes out of it.”
It has been reported Ealing Studios are to begin shooting the movie in Edinburgh in March next year.