EXCLUSIVE: Zac Efron goes NSFW dishing on Robert De Niro in 'Dirty Grandpa'

Before you go, we thought you'd like these...
Before you go close icon
EXCLUSIVE: Zac Efron Goes Very NSFW Fanboying Over Robert De Niro in 'Dirty Grandpa'

Dirty Grandpa may be one of Robert De Niro's most raunchy, insane roles to date, and even playing a perverted old man, the iconic actor had everyone else on set star struck.

In ET's exclusive behind-the-scenes look at the NSFW comedy, De Niro's co-star, Zac Efron, can't contain his admiration for the legendary star.

"The coolest character in the movie, by far, is Dick, played by the one and only Robert De Niro," Efron shared.

WATCH: Zac Efron Is Now Nearly Naked on the Set of 'Dirty Grandpa'

Aside from being effortlessly cool, De Niro once again got the opportunity to show off his comedy chops, and absolutely killed. According to Efron, it was hard not to crack up during every scene.

21 PHOTOS
Zac Efron general
See Gallery
EXCLUSIVE: Zac Efron goes NSFW dishing on Robert De Niro in 'Dirty Grandpa'
WESTWOOD, CA - APRIL 28: Actor Zac Efron attends Universal Pictures' 'Neighbors' premiere at Regency Village Theatre on April 28, 2014 in Westwood, California. (Photo by Jason Merritt/Getty Images)
NEW YORK, NY - MAY 07: Zac Efron visits 'The Tonight Show Starring Jimmy Fallon' at Rockefeller Center on May 7, 2014 in New York City. (Photo by Theo Wargo/NBC/Getty Images for 'The Tonight Show Starring Jimmy Fallon')
LOS ANGELES, CA - APRIL 28: Actor/producer Seth Rogen (L) and actor Zac Efron pose at the after party for the premiere of Universal Pictures' 'Neighbors' at The Armand Hammer Museum on April 28, 2014 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)
WESTWOOD, CA - APRIL 28: Actor Zac Efron attends Universal Pictures' 'Neighbors' premiere at Regency Village Theatre on April 28, 2014 in Westwood, California. (Photo by Kevin Winter/Getty Images)
LOS ANGELES, CA - APRIL 13: Actor Zac Efron accepts the Best Shirtless Performance award for 'That Awkward Moment' onstage at the 2014 MTV Movie Awards at Nokia Theatre L.A. Live on April 13, 2014 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for MTV)
LOS ANGELES, CA - APRIL 13: Actor Zac Efron attends the 2014 MTV Movie Awards at Nokia Theatre L.A. Live on April 13, 2014 in Los Angeles, California. (Photo by Michael Buckner/Getty Images)
HOLLYWOOD, CA - MARCH 02: Actor Zac Efron backstage during the Oscars held at Dolby Theatre on March 2, 2014 in Hollywood, California. (Photo by Christopher Polk/Getty Images)
Actor Zac Efron arrives on the red carpet for the 86th Academy Awards on March 2nd, 2014 in Hollywood, California. AFP PHOTO / Robyn BECK (Photo credit should read ROBYN BECK/AFP/Getty Images)
LOS ANGELES, CA - JANUARY 27: Actor Zac Efron arrives to the premiere of Focus Features' 'That Awkward Moment' at Regal Cinemas L.A. Live on January 27, 2014 in Los Angeles, California. (Photo by Alberto E. Rodriguez/Getty Images)
NEW YORK, NY - JANUARY 22: Actor Zac Efron attends the 'That Awkward Moment' screening at Sunshine Landmark on January 22, 2014 in New York City. (Photo by Cindy Ord/Getty Images)
SAN FRANCISCO, CA - JANUARY 14: Michael B. Jordan, Miles Teller and Zac Efron tour the Twitter headquarters on January 14, 2014 in San Francisco, California. (Photo by Kimberly White/Getty Images for FilmDistrict)
Actor Zac Efron attends the Los Angeles Lakers vs Minnesota Timberwolves NBA game at Staples Center on December 20, 2013 in Los Angeles, California. AFP PHOTO / Robyn Beck (Photo credit should read ROBYN BECK/AFP/Getty Images)
NEW YORK, NY - APRIL 19: Actor Zac Efron attends the 'At Any Price' New York premiere during the 2013 Tribeca Film Festival on April 19, 2013 in New York City. (Photo by Stephen Lovekin/Getty Images for Tribeca Film Festival)
AUSTIN, TX - MARCH 16: Actor Zac Efron speaks at the screening for 'At Any Price' during the 2013 SXSW Music, Film + Interactive Festival at the Paramount Theatre on March 16, 2013 in Austin, Texas. (Photo by Michael Buckner/Getty Images for SXSW)
TORONTO, ON - SEPTEMBER 14: Actor Zac Efron attends the 'The Paperboy' premiere during the 2012 Toronto International Film Festival on September 14, 2012 in Toronto, Canada. (Photo by Jemal Countess/Getty Images)
TORONTO, ON - SEPTEMBER 09: Zac Efron signs autographs at the 'At Any Price' premiere during the 2012 Toronto International Film Festival at the Princess of Wales Theatre on September 9, 2012 in Toronto, Canada. (Photo by Mark Davis/Getty Images)
VENICE, ITALY - AUGUST 31: Actor Zac Efron attends the 'At Any Price' premiere during the 69th Venice Film Festival at the Palazzo del Cinema on August 31, 2012 in Venice, Italy. (Photo by Gareth Cattermole/Getty Images)
US actor Zac Efron arrives for the screening of 'At any price' during the 69th Venice Film Festival on August 31, 2012 at Venice Lido. 'At any price' is competing for the golden Lion in the Venezia 69 section of the festival. AFP PHOTO / GABRIEL BOUYS (Photo credit should read GABRIEL BOUYS/AFP/GettyImages)
VENICE, ITALY - AUGUST 31: Actor Zac Efron attends the 'At Any Price' premiere during the 69th Venice Film Festival at the Palazzo del Cinema on August 31, 2012 in Venice, Italy. (Photo by Gareth Cattermole/Getty Images)
HOLLYWOOD, CA - JUNE 08: Actors Zac Efron and Ashley Tisdale arrive at the premiere of Warner Bros. Pictures' 'Rock of Ages' at Grauman's Chinese Theatre on June 8, 2012 in Hollywood, California. (Photo by Frazer Harrison/Getty Images)
of
SEE ALL
BACK TO SLIDE
SHOW CAPTION +
HIDE CAPTION

"I would break constantly, because the stuff that would come out of his mouth was insane," Efron, 28, recounted.

Even veteran actor Danny Glover was blown away by his chance to share the screen with the 72-year-old Oscar winner, who said his scenes with De Niro are definitely "gonna be in my sizzle reel."

WATCH: Zac Efron Talks About Being Intimidated Working With 'Legend' Robert De Niro

For some unsavory details about one scene involving Efron's butt and De Niro's thumb, watch the clip now!

Dirty Grandpa hits Blu-ray and DVD on May 17.

WATCH: Zac Efron and Robert De Niro Go Shirtless, Flex Their Muscles in 'Dirty Grandpa'

NSFW: Watch Zac Efron Do The Macarena Nearly Naked in 'Dirty Grandpa'

More on AOL Entertainment:
Kelly Ripa's return to 'Live': High stakes for everyone involved
Kylie Jenner puts curves on display in teeny, yellow bikini
Lady Gaga mourns Prince on social media


Read Full Story

From Our Partners