The former ‘Pop Idol’ champion admitted that the veteran judge could have ended up getting ill after eating one of his creations on a Sport Relief edition of the BBC baking show.
Speaking on Jo Whiley’s Radio 2's show, Will said: "I will just tell you, I am the worst baker you have ever seen.
"I almost poisoned Mary Berry! You'll just have to wait and find out [how]. I could have been thrown in the Tower of London for that.
"I didn't mean to do it [but] it was all fine... It was brilliant, though, and I did get a little taste for baking but perhaps under a very watchful eye," he added.
He’s set to appear on next Wednesday’s (24 February) episode of the show, competing against Alison Steadman, Ade Edmondson and Morgana Robinson.
‘The Great Sport Relief Bake Off’ airs Wednesday at 8pm on BBC One.