The "Office" star Angela Kinsey had no clue who Billie Eilish was when the pop star approached her for a photo once.

"I was at the airport and there was a really cute gal in a jumpsuit, like a big boxy jumpsuit," Kinsey recalled during an appearance on Monday's episode of "The Ellen DeGeneres Show," which was coincidentally guest-hosted by her costar Ellie Kemper (Erin Hannon), with the fellow "Office" alum Jenna Fischer (Pam Beesly).

"It was sort of an odd-fitting jumpsuit, and she came up to me and she was like: 'I love "The Office." Can we take a picture?' And I was like, 'Sweet person in a big jumpsuit, yes,'" Kinsey continued.

The actress, known for her role as Angela Martin on "The Office," went on to say: "And we took a selfie and then all of a sudden my Instagram was going crazy because this girl named Billie Eilish posted a photo of me and her."

Angela Kinsey, Jenna Fischer, and Ellie Kemper on "The Ellen DeGeneres Show." The Ellen Show/YouTube

"She was so sweet," Kinsey said, adding that she didn't know who Eilish was because the actress was "a dinosaur."

She did Google the pop singer, who turned 18 this month, and concluded that "she's a very talented young lady."

Fisher also chimed in and recalled her response when Kinsey told her about the encounter.

"Angela told me and I was like, 'Who is she?' And we're like two old ladies. We were like, 'Well, she's very popular with today's youth.' Her music speaks to them.'"

"And she's very fashion-forward," Kinsey said of Eilish.

In March, Kinsey posted the aforementioned photo with Eilish on Instagram and congratulated the "Bad Guy" singer on the release of her debut album, "When We All Fall Asleep, Where Do We Go?"

"We met at the San Francisco airport awhile back and I'm a dinosaur so I had no idea how talented you are!! I have loved catching up with you on Instagram. And the song 'My Strange Addiction' has a nice lil' snippet from 'Threat Level Midnight!' Your #theoffice Mom is over here rooting for you! Way to go!" Kinsey captioned the post, referring to Eilish sampling an episode of "The Office" on her song "My Strange Addiction."

Congrats @wherearetheavocados on your new album... When We All Fall Asleep, Where Do We Go? We met at the San Francisco airport awhile back and I’m a dinosaur so I had no idea how talented you are!! I have loved catching up with you on Instagram. And the song My Strange Addiction has a nice lil’ snippet from Threat Level Midnight! Your #theoffice Mom is over here rooting for you! Way to go! 😉 A post shared by Angela Kinsey (@angelakinsey) on Mar 29, 2019 at 10:12am PDT Mar 29, 2019 at 10:12am PDT

The same photo, plus another one, was shared by Eilish back in March 2018.

A post shared by BILLIE EILISH (@billieeilish) Mar 9, 2018 at 1:14pm PST

Fans of Eilish know that she's obsessed with "The Office." In addition to sampling the show, which Steve Carell (Michael Scott) said gave him a lot of credibility with his kids, she has met a few of the cast members.

In July, Creed Bratton shared a photo of himself greeting Eilish after attending what he called an "incredible" show by her and her older brother, Finneas O'Connell.

Billie Eilish and I hugging it out after her and her brothers incredible show last night. A post shared by Creed Bratton (@creedbratton) on Jul 10, 2019 at 12:50am PDT Jul 10, 2019 at 12:50am PDT

Before that, the pop star met Rainn Wilson (Dwight Schrute), and he quizzed her on her knowledge of "The Office" in a video for Billboard.

I met one of the most intense OFFICE fans of all time, William Eyelash aka @WhereAreTheAvocados. She won a yoghurt lid medal for her preposterous knowledge of the show. What an honor. This is a remarkable young human being that touches hearts, blows minds and F*%#n ROCKS! A post shared by Rainn Wilson (@rainnwilson) on Apr 19, 2019 at 6:09am PDT Apr 19, 2019 at 6:09am PDT

Eilish also caught the attention of Mindy Kaling (Kelly Kapoor) after the actress learned about "The Office" being sampled on her song.

Eilish rose to fame after releasing a song called "Ocean Eyes," which was written and produced by O'Connell, on SoundCloud in 2015. But in 2019 she became a breakout artist with her album, which included songs like "Bad Guy" and "When the Party's Over."

She also made history as the first artist born in the 2000s to have a No. 1 album on the Billboard 200 chart, appeared at Coachella, made her "Saturday Night Live" debut with a trippy, gravity-defying performance, and got nominated for six Grammy Awards. Plus, she made history as the youngest artist to be nominated in all of the show's top categories.

Eilish is known for her dark-pop sound and whisper-like vocals, in addition to her unique fashion sense. She frequently wears baggy clothing and previously said that she refrained from donning form-fitting outfits for fear of being sexualized or body-shamed.

Watch the video below (Kinsey talks about Eilish at 1:38).