Guy Williams joke about Christian music ignites fierce debate after Brooke Fraser Grammy win

Guy Williams has apologised for a joke about Christian music he made while congratulating Brooke Fraser on her Grammy win.

The Jono and Ben star continued to poke fun during The Project NZ on Monday night, where he suggested to Fraser the best Christian music simply replaces the word "baby" with "Jesus".

Williams took to Twitter on Monday to joke that Fraser would've been happy the win, until she realised it was for the category of Best Contemporary Christian Music Performance/Song.

After several negative replies, he posted an apology on Tuesday morning.

"A lot of people were genuinely offended by this tweet," he said.

"It was a throwaway comment that I thought was funny, but I don't wanna ruin peoples day and stuff! Sorry."

Fraser won the Grammy for 'What A Beautiful Name', which she made with Australian Christian group Hillsong Worship.

Following Williams' tweets, some replies slammed the church group for being anti-LGBT rights and "creepy as hell", others attacked the Grammys for only acknowledging one religion, while others defended Williams' right to tell offensive jokes.

Among the angry responses was one person calling Williams a "gutless dickhead" who wouldn't joke in a similar way about a "Muslim song" - along with what is presumably a slur directed at his relationship with Green MP Golriz Ghahraman.

Williams responded with another joke.

On The Project NZ, Fraser and Williams spoke after he'd tweeted the original tweet.

It wasn't mentioned, and she was happy to play along with his jokes; singing the chorus to Justin Bieber's 'Baby', but replacing the word "baby" with "Jesus".

Newshub.