Ansel Elgort is considered among the most bankable young actors around with the box-office successes of "The Fault in Our Stars" and "Divergent." But he's a fan first and foremost so imagine his embarrassment when his mom didn't recognize Bruce Willis.

The 20-year-old was one of the guests of "The Tonight Show Starring Jimmy Fallon" on Tuesday and Ansel Elgort recounted the time when his mother, Grethe Barrett Holby, greeted Bruce Willis but didn't know who he really was.

"Going to The Oscars is epic and she loved going, but she had no clue who anyone was, which was hilarious," he said. "We were at a party. Bruce Willis was there with his wife (Emma Heming) and they were introduced to my mom and she said, 'Oh hi, what's your name?'"

"And he said, 'I'm Bruce.' And she said, 'What do you do? Your wife's a model.' And he said, 'I'm an actor.' And she said, 'Oh my son's an actor. How's that going for you?' And he said, 'It's going pretty good.' I was like dying," the lead star in "The Fault in Our Stars" added.

Speaking of "The Fault in Our Stars," the movie starring Ansel Elgort and Shailene Woodley received nominations for the 2015 MTV Movie Awards.

"'The Fault In Our Stars,' about two cancer-stricken teens falling in love, landed nominations for its leading duo Shailene Woodley and Ansel Elgort in the best female and male performance, best duo and best kiss categories," said Daily Mail.

The Ansel Elgort and Shailene Woodley-starrer, "The Fault in Our Stars" will also be pitted against "Guardians of the Galaxy," "American Sniper," "The Hunger Games: Mockingjay - Part 1,″ "Gone Girl," "Boyhood," "Whiplash," and "Selma" for the category Movie of the Year in MTV Movie Awards. The Oscar winner "Birdman" wasn't included in the youth-oriented plum.