Former defence minister Christopher Pyne spoke with EY about his life after politics while still an MP, before accepting a defence-focused role with the professional services giant.
The firm has revealed the timeline in its submission to a Senate inquiry.
The inquiry is looking at whether Mr Pyne and former foreign affairs minister Julie Bishop - who retired from politics at the May election - have breached ministerial standards through their post-politics jobs.
The standards says ministers must not lobby or have business meetings with politicians or public servants within 18 months of leaving parliament, on matters they dealt with in their final 18 months in office.
Mr Pyne has picked up a job advising EY on defence issues, while Ms Bishop has been appointed to the board of a foreign aid contractor.
In EY's submission, the firm's Defence Industry Leader Mark Stewart says he met with Mr Pyne on April 8 to discuss his retirement from politics.
"EY subsequently formed a view that Mr Pyne's 26 years' experience as a politician would be beneficial to EY's strategy in growing our defence industry practice, via engaging him as a consultant," Mr Stewart wrote.
EY formally offered Mr Pyne such a job on April 17, less than a week after Prime Minister Scott Morrison called the election on April 11.
He accepted the position on April 20, suggesting a start date of June 1, though his agreement began on June 7.
Under the agreement, Mr Pyne will provide consulting services for two days a month for a period of six months, with an option to extend.
Mr Stewart said ultimately, "only Mr Pyne" can ensure he complies with the ministerial standards.
But he stressed the firm has not, and will not, seek that Mr Pyne do anything that would breach them.
In a report tabled in parliament last month, Department of Prime Minister and Cabinet boss Martin Parkinson cleared Mr Pyne and Ms Bshop of breaking ministerial guidelines over their post-politics jobs.
Australian Associated Press