George RR Martin: In my lifetime, there has never been a presidential candidate more unfit to lead this nation than Donald Trump!!!

George RR Martin has claimed that, in his lifetime, no presidential candidate has been "more unfit to lead this nation" than Donald Trump before joining Hillary Clinton's campaign in New Mexico.

The author appears to have taken a break from writing two of the remaining books in his acclaimed series, A Song of Ice and Fire adapted for TV as A Game of Thrones, to encourage early voting and explain in detail why he believes that the Republican candidate is not fit for office.

On Saturday, the Hillary Clinton for New Mexico campaign Twitter account posted a photograph of the author which reads "'Hold the door!' George R.R. Martin surprised volunteers in Santa Fe today to encourage early voting" and links to a DNC voting tool.

The previous day, the 68-year-old explained his reasons for backing the Democratic candidate over Mr Trump in a blog post published on LiveJournal. 

The acclaimed author warned that New Mexico, which voted for Barack Obama in the past two elections, has returned to its previous "battleground" status in 2016.

In the post, Martin explained how he compared adverts aired by the two camps in the state, where he lives, and observed that "Trump's ads against Hillary [...] are made of assertion, innuendo, and name-calling, but there's no substance to them." Meanwhile, "Clinton's ads just show Trump being Trump."

"You don't need to like Hillary. You don't need to listen to what Hillary says about Trump, or what I say about Trump. You just need to listen to Trump. If you can do that, and still consider voting for him... well..."

He continues: "Pappy Bush lost an election by looking at his watch. Michael Dukakis lost an election by riding around in a tank. Howard Dean lost an election by giving a yeeeehah scream. Trivial things. Insignificant things. Trump, on the other hand, has said the vilest things any presidential candidate has said since George Wallace, and he's rising in the polls. "

"He has boasted that he could shoot someone dead on Fifth Avenue and still not lose any votes. I am beginning to think he was right," Martin concludes.