Though he never ran for office, politics surroundedJohn F. Kennedy Jr.for all of his life.
The eldest son of an assassinated president, Kennedy made what was then considered his debut into the world of politics at the 1988 Democratic National Convention, where he introduced his uncleTed Kennedy, a longtime senator. (A decade later, Kennedywould die at 38 in a plane crashwith his wife and sister-in-law.)
While his DNC speech was acclaimed — it wasreportedly met with“a two-minute standing ovation” — newly released video from Kennedy’s prep sessions reveal the bumps before the polish.
In an exclusive preview from A&E’sBiography: JFK Jr. The Final Year, premiering Tuesday night, Kennedy’s friend Steven M. Gillon recalls how he obtained never-before-seen video of Kennedy, then 27, rehearsing his speech.
“It’s interesting to see how rough these practice sessions were and then how smooth he was when he actually delivered the speech,” Gillon says in the preview.
Earlier this month he releasedAmerica’s Reluctant Prince, a nuanced biography of Kennedywhich reveals the complicated life he ledbeneath the legacy of his family name.
“He said he was two people,” Gillon, who met John at Brown University in 1981, sparking an 18-year friendship,recently told PEOPLE.
John F. Kennedy Jr.David Hume Kennerly/Getty

“He said he played the role of John Fitzgerald Kennedy Jr., the son of the president,” Gillon said then. “But at his core, he was just John.”
In theBiographyclip, the rehearsal video shows Kennedy as he memorizes and reviews his speech about his uncle.
“I think John had that instinct: He got up there in front of those people and he just turned it on,” Gillon says.
Long a charmer, at ease in the spotlight that shone on him since birth, Kennedy had grown more accepting as an adult of the idea that his true calling was politics — like his father and uncles before him.
In his last months, Gillon previously told PEOPLE, “John was becoming more comfortable with his political ambitions. He wanted to run for governor of New York and his ultimate goal was to return to the White House.”
• For more on JFK Jr.’s world and sudden death, pick up PEOPLE’s 96-page special editionJohn F. Kennedy: An American Life, available nowon Amazonand wherever magazines are sold.

Speaking in theBiographypreview, journalist and former presidential speechwriter Hendrik Hertzberg describes the buzz from Kennedy’s DNC speech a year before the Bush inauguration comment.
“He hit it out of the park,” Hertzberg says. “The whole world at that moment thought, ‘Wow, he’s going places. He’s not just Jr.’ ”
Biography: JFK Jr. The Final Yearairs Tuesday (9 p.m. ET) on A&E.
source: people.com