BBC NI programme 'The View' has seen a confidential letter sent by Ian Paisley Jr to the first minister in 2009.
In it, Ian Paisley urged Mr Robinson not to give Mr Larkin the job saying they would be "mad to make this appointment".
He warned the first minister that an attorney general had to be, "someone whom you must implicitly trust and who you know, once appointed, will be difficult to remove".
Mr Paisley also wrote: "I think the government should steer away from appointing this controversial personality, who will only seek to build on his growing ego to the detriment of the government, and dare I suggest, the personal embarrassment of ministers not least yourself."
The politician, who was a DUP MLA at the time, told the first minister that he should consider other people for the position.
"There are numerous other safer candidates, not least for us as a party that I believe we ought to consider. You may be aware of the fact that Mr Larkin unfortunately has form regarding his misconduct," Mr Paisley said.
Paisley warning Robinson about someone being egotistic is priceless.