Mattis writes letter of recommendation for Reince Priebus to join the Navy

The program is fairly common practice for the Navy, and has become known as a way for politicians to gain military experience.

"Secretary Mattis agreed to write a letter of recommendation on his behalf. The letter is consistent with applicable standards," said chief Pentagon spokesperson Dana White on Friday.

The Washington Post first reported that Priebus was joining the Navy, citing a memo obtained by the paper.

The process allows for career professionals to contribute their field's experience, but in the capacity of serving in the US military, and those accepted will generally go to Newport, Rhode Island, for two weeks of training.

According to The Washington Post, Priebus wrote in a statement to the Navy that he had seen his sister serve as a Navy doctor and had memories of his father teaching at Naval Station Great Lakes in Illinois.

Priebus also noted in his statement submitted to the Navy that he was particularly moved to serve following his meeting in the Oval Office during his time as chief of staff with the family of Senior Chief William Ryan Owens -- a Navy SEAL who died in a special operations raid in Yemen, the Post reported.

"At that moment, the gravity of every action we take in the West Wing rushed down upon my shoulders," Priebus wrote, the paper reported. "Everything suddenly became extremely real and raw. As some time passed, a few other senior aides joined me in the Cabinet Room and we discussed the consequences, harsh realities and weight of what we do every day."