Paul Anthony Kelly reveals how he nailed voice of JFK Jr.

Paul Anthony Kelly had a ritual before he got to the set everyday to play John F. Kennedy Jr.

In the new FX series Love Story: John F. Kennedy Jr. & Carolyn Bessette, Kelly, 37, makes his screen debut as America's beloved bachelor opposite Sarah Pidgeon as Carolyn.

The actor had little time to prepare for the role before filming began and so he used all the material available on JFK Jr.'s personality.

"I really had to tighten up my bootstraps and do deep dives, learn everything I could," Kelly told People. "Luckily, with John, there's a wealth of information. He's a very well-documented individual, so I was able to consistently go back and rely, review, interpret that information."

Getting the heartthrob’s "vocals down" was a big priority.

"He narrates his father's book, Profiles in Courage, so I would listen to that every day before getting to set," shared Kelly. "I'd do my little breathing exercises and then put that on and do a little hear and repeat."

"I'm very, very fortunate in that," added the actor.

Sharing more insight into how he prepared, he added, "The whole prep process was very full-on from the moment I was cast."

"There wasn't a whole lot of time before we started shooting it. The whole team here really set me up for success," he shared, adding that he had "a dialect coach, acting coach, a physical trainer" as well as a "meal plan".

Love Story: John F. Kennedy Jr. & Carolyn Bessette premiered on February 12.