What is most striking about Jackass Presents: Bad Grandpa is that it is heartwarming. Yes, the guys who brought us three movies under the moniker that says it all, Jackass, have delivered a film about a grandpa (yes, he is very bad) and his grandson that is hilarious as it should be from that filmmaking ensemble, but Bad Grandpa is also extremely heartfelt.

You would think, given the last three Jackass films, most recently Jackass 3D, that Bad Grandpa would be a series of hidden camera pranks centered on Johnny Knoxville’s 86-year-old comedic alter ego, Irvin Zisman. That would be a solid guess, but Bad Grandpa is so much more. There is an actual story here and it's acted out with a touch that is remarkable given its raunchy and frat-boy-driven pedigree.

The film begins with the grandson, Billy (Jackson Nicoll), in a lawyer’s waiting room while a hidden camera captures him telling strangers that his mother is going back to jail for drugs and that he remembers her breast milk tasted bad from all the crack she did. OK, this is a Jackass movie. Then, the mother in question comes out and grabs her son with the promise they’re going to see grandpa.

We then meet this Bad Grandpa in a doctor’s waiting room where he gets the bad news that his wife has just died. He smiles broadly, tells the nurse she made him so happy and heads out the door as Just a Gigolo by David Lee Roth plays.

And the film is off and running.

It hits the full-fledged “family” comedy mold when Billy is brought to his grandpa while he is in the middle of delivering her eulogy. We see how that goes in the Bad Grandpa trailer as the argument with his estranged daughter leads to a push and shove match that sends Grandpa’s wife falling out of her casket.

See, that’s the other thing that is incredible about Bad Grandpa. Even in the most recent Bad Grandpa red band trailer, there are a lot of jokes you have already seen. Oftentimes, comedies reveal too many of their punch lines in their teasers. Yes, we see the delivery of the action in the film that gives us our laugh-out-loud moments. They’re the same as in the teasers, yet, in the context of the full film, they are even funnier than even previously thought. That speaks to the comic strength of Knoxville and his talent. Yes, I said talent.

There are gifted improv comic actors, and then there is what Knoxville does. He has to react off of perfect strangers, completely unaware of the realm of what to even expect. Yet, the actor manages to deliver lines that have you falling out of your seat in laughing fits, while still moving his plot forward. It is an uncanny gift.

And his “grandson” is up for the task as well, and even comes off as a mini-Johnny Knoxville. Nicoll may be only eight years old, but he matches Knoxville note for note.

The two head out on the road as Bad Grandpa has to deliver his grandson his biological father across the country since mom is heading to jail. It is a road trip movie and it follows all the great elements that make a good film of that ilk (check out our Top 10 Road Trip Movies). There is a sweetness that is even reflected in the music and score that you half expect Tom Bodett to start narrating!

These two characters learn to like each other. Their comic adventures along the byways of America are simultaneously charming, outrageously funny (like this Bad Grandpa child beauty pageant clip), and believe it or not… possess an ending that might even make you tear up.

Yeah, seriously, the film has “Jackass” in the title, our Bad Grandpa review surprisingly finds, but it is all heart.