Katie Holmes kept antique Cartier watch from The Kennedys mini-series

Katie Holmes is the proud new owner of an antique Cartier watch after convincing TV producers it was essential for her portrayal of former U.S. First Lady Jackie Kennedy.

The Batman Begins star first played President John F. Kennedy's wife in 2011 TV series The Kennedys, and she has reprised the role for the new follow-up, titled The Kennedys: After Camelot.

Katie reveals there was one key accessory she wanted to wear to fully embody Jackie's style and character, and she lobbied producers until she got it.

"She (Jackie) had such impeccable taste and she was known for... (having) a beautiful Cartier watch...," the actress explained on U.S. breakfast show Good Morning America. "We found an antique Cartier watch, just for our wardrobe, 'cause I thought that that's very important 'cause we're gonna see that quite often, so I fought for that. I fought for that Cartier!"

And when filming on the historical project wrapped, Katie got to add the pricey piece to her own collection of watches.

"I didn't (have to return it), that's the best part!" she smiled.

The Kennedys: After Camelot, based on the book of the same name by J. Randy Taraborrelli, chronicles the political dynasty post-1968. The story begins when Robert 'Bobby' Kennedy is assassinated, five years after his brother John F. Kennedy, and Katie admits she was really struck by how emotionally and physically strong Jackie was throughout the family turmoil.

"She was so charming, but not a fool, and knew exactly what was going on and could read people very well," Katie said on U.S. talk show The View. "I guess her strength is something that I am continually amazed by.

"This woman went through so much in the public eye and did it with such grace."

Former Friends star Matthew Perry also stars in the mini-series as Robert and John's brother Ted Kennedy.