Kevin Spacey's fans are used to seeing him play the president of the United States. In Netflix's "House of Cards," the Oscar winner is thrillingly serious and intimidating as the Machiavellian Frank Underwood. As the real President Richard Nixon, however, he is all laughs. 

Spacey stars as Nixon in the comedic "Elvis & Nixon," which premiered at the Tribeca Film Festival Monday in New York City. The film, which was produced by Amazon Studios and Bleecker Street and will be available on Amazon for streaming, tells the behind-the-scenes story of how Elvis Presley, played by Michael Shannon ("Take Shelter," "Boardwalk Empire"), scored a one-on-one sitdown with Nixon in 1970 to become a federal agent in the war on drugs. 

The dynamic duo of Spacey and Shannon squeeze every laugh out of this historical oddity, elevating a film that sometimes feels hamstrung by its limited scope. 

Spacey's Nixon is welcome comedic relief from the Watergate-themed, semi-tragic depictions that populate most film adaptations of the controversial figure. Spacey's impression appropriately stays just shy of caricature, and it is great fun watching the always-calculating Nixon strain in a series of disingenuous attempts to charm the karate-chopping Elvis into a coveted photo op — he needs that youth vote! The stiff politician and the outlandish rocker make the perfect odd couple. 

Shannon, on the other hand, is a marvel as "the King." The Tribeca veteran — he also stars in the basketball drama "Wolves," which premiered at the festival last Friday — milks Presley's eccentricities (the karate, the outfits, the voice) for laughs, but never loses track of the tragic undercurrent beneath the surface — Presley's impromptu visit to the White House came at the onset of his deteriorating mental health.

Director Liza Johnson, working from a script by Joey Sagal, Hanala Sagal and Cary Elwes, deftly captures the historical context of the bizarre meeting for both sides. Despite the laughs, the Presley of "Elvis & Nixon" is lonely figure, crippled by the isolation of his fame, starving for purpose (in this case a federal badge) and wanting for love from the friends he insists bend over backwards to meet his every demand. Meanwhile, Nixon is as guilty as anyone else in failing to see the sad human being behind the iconic shades and, instead, seeking to profit off that image instead. 

However, in what is ultimately a movie about a photograph  — the film touts that the famous Presley-Nixon photo is the most requested from the Library of Congress archives  — "Elvis & Nixon" struggles to find a fulfilling arc. For Nixon, this was just a photo op; for Presley, just the most notable moment in a worsening pattern of odd behavior that continued until his death in 1977.

In Johnson's attempt to thread a heart into this story, she turns to Alex Pettyfer's Jerry Schilling, Presley's real-life childhood friend and a longtime member of his entourage. At the start of the movie, Schilling has forsaken the Elvis circus in favor of his fiancee (Sky Ferreira) and the promise of a quieter life as a filmmaker. However, Presley eventually guilt-trips Schilling into accompanying him to Washington to smooth-talk Nixon's aides, played by Colin Hanks and Evan Peters, and secure the presidential meeting along with fellow Elvis devotee Sonny (a game Johnny Knoxville). It is an earnest attempt, but ultimately amounts to a hollow storyline that feels upstaged by the fireworks coming from Spacey and Shannon.

Those fireworks, though, are well worth the price of admission.

Watch the trailer for "Elvis & Nixon" below: