And Kimmel wasn't happy, suggesting on Jimmy Kimmel Live! that English might even be worse than America's controversial leader.
"We can be pretty hard on Donald Trump but they have a guy in New Zealand, the Prime Minister of New Zealand, a gentleman named Bill English, who I think is even worse and I'm going to show you why," Kimmel said.
"Not only did he put (tinned spaghetti) on a pizza - he put it on a pineapple pizza. He put canned spaghetti and pineapples on a pizza.
"This mother... That is so offensive. That is an act of war.
"I think he just declared war on Italy ... and maybe Hawaii too."
Kimmel then called for New Zealanders to take control of the situation.
"Impeach that man immediately," he said.
English reportedly told MoreFM his children had forced him to make the pizza post.
"I quite often cook on a Monday night for the household and I had been goaded by my children about how my Facebook needed, every now and again, something a bit more personal," he said.
But a professional pizza chef told The Spinoff his spaghetti concoction didn't even deserve to be called "pizza".
Farina executive chef Sergio Maglione said: "It's more like round toast with stuff on top."
"For me, it's all about using the best and freshest ingredients available - no processed food."
English's pizza goes viral
English's pizza made headlines around the world, including Buzzfeed, who simply said: "This s*** is f***ed up."
In the UK, the Evening Standard ran with the headline: "New Zealand PM Bill English causes storm with 'atrocious' tinned spaghetti and pineapple pizza."
Metro went with this: "The Prime Minister of New Zealand thinks tinned spaghetti is an acceptable pizza topping."
And The Mirror wrote: "A man put something weird on his pizza and people can't decide whether it's a good idea."
The Huffington Post wrote: "New Zealand's Prime Minister Just Concocted A Crime Against Pizza."
The response
Many agreed with Jimmy Kimmel that Bill English's pizza creation was a sackable offence.
"Sorry Bill, any man who puts spaghetti on a pizza is not fit to run my country, you cannot count on my vote come election time," wrote one.
"I don't support your policies(Vote Green bois) but spaghetti on pizza is something i can get behind," said another.
"I might vote Labour now Bill. This is like sh*tting on Italy," said a third.
Some just pleaded with English to stop cooking.
"Bill please do not cook..."
But English's strange pizza methods weren't universally hated.
In fact, some agreed with him.
"Totally agree that spaghetti on pizza is yum....BUT....who else has noticed how runny canned spaghetti is nowdays," said one.
"It comforts me to know I have about the same level of culinary skill as our Prime Minister," said another.
But for one, the spaghetti wasn't the issue - it was the pineapple.
"I fully support your policies, and I am behind tinned spaghetti on pizza, however pineapple on pizza is a policy I cannot support."