Every so often a television movie comes along that leaves you speechless. It’s hard to find the right words to describe “America’s Prince: The John F. Kennedy Jr. Story” (7 p.m. Sunday, TBS). “Ghastly” comes close. But it’s that, and so much more. So if you’re like me and you take a perverse pleasure in train-wreck television, you won’t dare miss this. Have your friends over for a viewing party — or, in this case, a viewing wake. You’ll howl. You’ll growl. You will throw things at the screen! I guarantee it.

“Prince” begins with actual news reports of the 1999 plane crash that killed young Kennedy (Kristoffer Polaha), his wife, Carolyn Bessette (Portia de Rossi), and her sister Lauren.

Mixing newsreel footage and bad re-creations, “Prince” manages to stage morbid flashbacks within morbid flashbacks. Whenever the action flags, we can always count on grainy shots of (the real) young John saluting President Kennedy’s coffin, or staged re-creations of (a fake) young John playing under his famous father’s desk.

Just when you think “Prince” can’t get any more tasteless, another scene unfolds that leaves you gasping. In one of the film’s many absurd moments, John looks up from his bed, where he has just consummated his relationship with Bessette, to glance at a photo of his martyred dad staring down at him, as if to say, “Job well done.” I am not making this up.

Tonight’s highlights

• The Philadelphia Eagles take on the Atlanta Falcons in NFL playoff action (7 p.m., Fox).
• Will Smith, Gene Hackman and Jon Voight star in the 1998 drama “Enemy of the State” (7 p.m., ABC).
• Hackman also stars as the patriarch of a quirky Manhattan family in the 2001 comedy “The Royal Tenenbaums” (7 p.m., Starz).
• Denzel Washington was rewarded with a Best Actor Oscar for his turn in the 2001 police drama “Training Day” (7 p.m., HBO).
• Chefs compete for their just desserts in the “$50,000 Pastry Challenge” (8 p.m., Food).