Pakuranga MP Maurice Williamson has been given the go-ahead to appear on the popular Ellen DeGeneres show after his speech in support of gay marriage made a him a hit on YouTube.



Prime Minister John Key this morning joked about making Williamson his senior speech-writer.



"He is very funny and there is always a serious message in there," Key said.



"He is ferociously bright."



Williamson, who has been described as a "gay icon" since his speech - a description he said was news to his wife - originally declined the invitation to go on the chat show because rules prevented him from receiving a free trip and an appearance fee.



But Key has approved it as long as the fee is donated to charity.



In his speech on the Marriage Equality Bill, Williamson, an MP since 1987, joked about claims the drought was caused by the law change, saying it was pouring with rain in his electorate and there was an "enormous big, gay rainbow" above it.



"It has to be a sign," he said.



Williamson said he had been warned he would "burn in the fires of hell for eternity" for backing the law change, but that was a mistake because he had a physics degree and had worked out he would only last for 2.1 seconds in a furnace.



He rejected the bullying tactics by some opponents of the law change.



He could not see why people would oppose two people in love expressing that through marriage, saying: "I can't see what's wrong with that for love nor money."