Paul McCartney allegedly sent his baby daughter's poop to a music critic following a negative review.

In the new book, 'Wings: The Story of a Band on the Run', drummer Denny Seiwell recounted the time the Beatles icon agreed to take an unnamed journalist along to a soundcheck for a Wings concert in the 1970s.

Wings, known for songs like 'Band On The Run' and 'Live and Let Die', were active from 1971 until 1981.

But while the critic didn't stay for the show, he still wrote a "full-on review" of the gig and "slagged" off the group.

According to Denny, Paul and wife Linda McCartney sought to get revenge by sending the writer a gift courtesy of their then-baby daughter Stella McCartney.

"Stella was a baby at the time," he stated, per an extract obtained by The New York Post. "So Paul and Linda took one of those little plastic soap dishes from the hotel we were in, and they got one of Stella's turds, put it in the soap dish, wrapped it up, and sent it to him."

Denny went on to note that he didn't know if the journalist responded to the prank.

"You heard that from me. I don't care if they want it to be known or not," the musician added. "I thought it was the perfect response to a crude British pressman."

Representatives for Paul have not yet responded to the story.

The legendary musician and Linda were married from 1969 until her death from breast cancer at the age of 56 in 1998. The couple shared daughters Mary, 56, Stella, 54, and son James, 48.

'Wings: The Story of a Band on the Run', which is described as an "oral history of a band that came to define a generation", is out now.