Elvis and Nixon

Put two larger-than-life figures in the same room and let the sparks fly. That’s the basic premise for Elvis and Nixon, a breezy comedy that speculates on the moments leading up to the popular 1970 Oval Office photo of arguably the two most famous men in the world at the time.

If only the film was fully committed to that concept, it might have been more consistently amusing instead of providing only scattered moments of nostalgic charm when the two “recording artists” are apart.

The film focuses on the bizarre ramblings of Elvis (Michael Shannon) wanting to become a government “federal agent-at-large” in order to go undercover and ostensibly steer teenagers away from drugs.

So he heads to Washington, D.C., for a hastily arranged meeting with President Nixon (Kevin Spacey) to outline his plans. After some consternation, Nixon and his staff agree to host Elvis — before an afternoon nap on the president’s schedule — although the president is initially more concerned with getting an autograph for his daughter. After an awkward introduction, they find some common ground.

Like its source material — the film points out that the photo is the most requested among the millions available in the National Archives — Elvis and Nixon has the feel of a pop-culture novelty item.

As directed by Liza Johnson (Hateship Loveship), the film has fun with the outrageous hair and costumes of the period and with the caricatured portraits of both men. Eventually it gets down to business, whether it’s Elvis ignoring White House protocol or the irascible Nixon becoming starstruck in his own office. Along the way, their small talk includes only vague discussions of politics.

The actors charismatically banter back and forth, with Spacey playing a true-life presidential role that’s just as notorious as his fictional commander-in-chief on “House of Cards.” Shannon mimics Elvis’ voice and mannerisms to amusing effect, even if he looks nothing like him.

Yet considering its dynamic subjects, the film lacks sufficient spark in the first half, which is consumed mostly with Elvis’ quirky travel adventures. Seeing him away from the stage certainly doesn’t showcase his more endearing qualities.

The satirical energy picks up considerably once the King finally arrives at the White House, but the two halves are so different that it’s worth considering whether the material would have worked better as a one-act play — before he leaves the building.

Rated R, 87 minutes.