Malorie Blackman has said she “called it” after US doctors transplanted a pig’s heart into a patient, mirroring the plot of one of her early novels.

The author wrote about a similar operation in her 1997 children’s book Pig Heart Boy, the story of 13-year-old Cameron Joshua Kelsey who has a serious heart condition.

Cameron accepts experimental surgery from a transgenics expert and becomes the subject of intense media attention.

The book was shortlisted for the Carnegie Medal literary award and adapted for TV by the BBC.

Responding to news of the transplant, 59-year-old Blackman wrote on Twitter: “I hope it works out for the man involved. Can’t help but have a little smile though.”

The Noughts & Crosses writer added the hashtags #calledit and #PigHeartBoy.

In a second tweet, Blackman said: “More info on the world’s first pig heart transplant – xenotransplantation from a genetically modified pig.

“At least I got my facts correct in my book Pig Heart Boy! Good luck to David Bennett.”

The surgery at the University of Maryland Medical Centre in Baltimore last Friday took seven hours.

The pig was genetically engineered so its organs could survive in a human body.

Patient David Bennett is reported to be doing well and breathing on his own without a ventilator.

The 57-year-old was not eligible to be put on the transplant list and is said to have thought that medics were joking when the operation was initially proposed.

In Pig Heart Boy, Cameron’s father secretly contacts transgenics expert Dr Richard Bryce before the operation is offered as an option to his son, who has been diagnosed with a terminal condition.

Like Mr Bennett, Cameron initially responds with shock at the idea.