Rex Tillerson has revealed that he did not want the job as US secretary of state and only took it because his wife convinced him to.

As he prepares for his biggest event since taking the job - a 68-nation meeting to discuss the fight against the so-called Islamic State - the former oil executive said he was "stunned" when the then-president-elect Donald Trump summoned him to Trump Tower in New York and offered him the role as America's top diplomat.

“I didn’t want this job; I didn’t seek this job,” he told the Independent Journal Review.

Rex Tillerson was Donald Trump's pick for US secretary of state Credit: PA

The 65-year-old Texan said he had expected to retire after four decades at ExxonMobil to "go to the ranch to be with my grandkids" until his wife Renda St Clair intervened.

“My wife told me I’m supposed to do this."

Mr Tillerson has been heavily criticised in the early weeks of his tenure, with critics accusing him of being out of his depth and unwilling to fight a hostile White House seeking to impose deep budget cuts on his department.