As fans of BGT will know, the banter between new judge David Walliams and Simon Cowell – who are pictured above, apparently auditioning for the Wallace & Gromit lookeylikey trials – has been both relentless and very funny…

David has of course taken to calling Cowell “my Simon”, and Simon has taken to giggling while uttering “Shut up David” repeatedly.

However, while speaking to the PA about his forthcoming new childrens’ book – he’s already written four – David revealed that he got the inspiration for the book’s villain by basing the character on Simon.

While explaining the plot of the new book, David said, “It’s about a little girl who befriends a rat and this one has a really evil villain in it.

“He’s the one who wants to turn that rat into a burger…

“It’s based on someone who was on Britain’s Got Talent… and it’s not (fellow judges) Amanda Holden or Alesha Dixon.”

And when asked whether his book’s bad guy “could ever be as evil” as Simon, David joked, “I’d like to but it’s hard to outstrip reality.”

Meanwhile, David’s fellow BGT judge Amanda Holden has offered Simon some advice, which is that he should keep The X Factor’s fourth judge spot vacant so as to invite guest judges throughout this year’s series.

Speaking to The Sun about her advice to Simon, which I’m sure he’ll heed, not, Amanda said, “It keeps it fresh. Simon should keep it like that.”

However, she added, “But no amount of guest judges will make up for the fact they don’t have a dancing dog on their show.”

True dat.