A dead man confesses: How that ‘War With Grandpa’ casket scene with De Niro went hilariously wrong

Veteran character actor James Martin Kelly heard the words every actor dreams about when he was cast as Carl in "The War With Grandpa" (in theaters now).

Kelly was told he would appear in a scene with two of this generation's greatest actors: Robert De Niro and Christopher Walken.

"The good news is you're working with De Niro and Walken," Kelly, 66, recalls being told by the casting director. "The bad news is, you're dead."

Kelly, whose Chief Duffy character chewed out Dennis Franz's Andy Sipowicz in "NYPD Blue" and who played Channing Tatum's boss in "Magic Mike," jumped at the chance to appear in a casket as Carl – even though it was clearly not a speaking part.

"You're working with these two guys, legends," says Kelly. "It was so awesome to have the chance."

Snakes, shaves, dodgeballs: Robert De Niro endures his greatest film blows in 'The War With Grandpa'

He also knew it was going to be an unusual experience playing Carl, whose funeral is attended by his longtime adventure buddy Jerry (Walken), with Ed (De Niro) coming along to support his friend.

During his suit fitting, the costume designer asked him to lie down on the floor to be measured, a first for Kelly. In a photo session, the actor hit power poses that were Photoshopped to be displayed as life memories next to the casket: Carl skydiving, climbing mountains, on a safari, wrestling a crocodile.

The Los Angeles-based actor went to work on a different project in Charleston, South Carolina, that ran late into the night before his "Grandpa" shoot. Kelly finished at 2 a.m. and drove overnight to Atlanta, where "Grandpa" was filming at Peachtree Christian Church.

He arrived just in time for his own funeral, finding his burial suit waiting for him at his trailer.

Kelly dressed and "jumped into the box," a two-section casket with a camera rig. The open setting was padded but constricting.

"I'm sort of claustrophobic and don't like tight spaces at all, and this was tight," says Kelly.

But as the afternoon progressed, Kelly relaxed into the role of the dearly departed friend in front of the two famous mourners. In the scene, Ed's new iPhone goes off loudly and he drops it into the coffin, causing De Niro to frantically rummage. When the phone slipped further than planned, Kelly never broke character, even as De Niro "began fishing around," says director Tim Hill. "Luckily, James held it together."

Then De Niro had trouble closing the lower portion of the casket in the scene.

"The lid kept popping back up and so he slammed it down repeatedly," says Hill, who used the "happy accident" in the final scene.

As the hours went by, a sleep-deprived Kelly got a little too comfortable portraying eternal slumber. Hill noticed during a break that his actor was likely asleep.

Kelly just remembers the startling vision of De Niro waking him up.

"Suddenly I hear someone calling my character's name, 'Carl, Carl, wake up.' And I open my eyes, and there's Robert De Niro's face that we all know, squinting and smiling and laughing. Six inches from my face, like almost touching noses," says Kelly. "Then I realized I had fallen asleep,"

De Niro and Walken both burst out laughing, with Walken having to walk away. The sleeping casket moment ended up in the "Grandpa" blooper reel shown during the credits, in which the beaming De Niro blurts out, "Carl, you're still alive!"

Hill was pleased with the stiff performance, describing Kelly as "a real trouper." Still, the chagrined Kelly says he apologized to De Niro for the temporary lapse.

"I said, 'I cannot believe I just did that,' " says Kelly. "He thought it was hysterical and said, 'Don't worry about it. I fell asleep yesterday, and I wasn't even dead.' So it really ended well. What an awesome gig."

This article originally appeared on USA TODAY: 'War With Grandpa': Robert De Niro casket scene went hilariously wrong