If you don't know what popular online trend "man crush Monday" is, you're not alone – neither does Dr. Anthony Fauci, the nation's top infectious disease expert. Thankfully, he had "good 4 u" singer Olivia Rodrigo on hand at the White House to explain it to him.

“Man crush Monday is just like – on Mondays, people post a picture of their boyfriends and be like, ‘ah, man crush Monday. This is why I love you.’ So it’s a big compliment,” the singer explained to the director of the National Institutes of Health in a new video.

What You Need To Know

  • Singer Olivia Rodrigo and White House chief medical adviser Dr. Anthony Fauci are featured in a new White House video released Friday

  • The video is part of the administration’s effort to encourage young Americans to get their COVID-19 vaccine, and was shot during Rodrigo's recent visit to the White House

  • Rodrigo and Fauci read fan tweets addressed to them both, with Rodrigo explaining what "man crush Monday" means to the doctor 

  • Rodrigo, 18, said she experienced some adverse symptoms after receiving her second jab against COVID-19, but was “fine in a couple hours” after taking a nap

The unlikely duo are featured in a White House video released Friday, shot during Rodrigo’s recent visit to 1600 Pennsylvania Avenue.

Friday’s video is part of the administration’s effort to encourage young Americans aged 12-27 to get their COVID-19 vaccine. According to a CDC report released last month, about 38% of people aged 18–29 had received at least one dose of a COVID-19 vaccine as of May 22, 2021, the lowest such age group. 

In the video, Rodrigo and Fauci read fan tweets addressed to them both, one of which says in part: “Happy man crush Monday to this hero. Thank you, Dr. Fauci for all the hard work you do.”

When the White House chief medical adviser reveals he isn’t sure what “man crush Monday” means, the “good 4 u” singer explains the reference – to which Dr. Fauci responds: “If man crush Monday makes you get vaccinated, go for it!”  

The two go on to answer more common questions about COVID-19 vaccines, with one tweet reading: “Are these chills from my second dose of the vaccine or from listening to deja vu by olivia rodrigo for the 174759385826th time today?” 

“Oh, my gosh. I hope they’re from ‘deja vu,’” Rodrigo jokingly responds. 

Fauci adds that the comment brings up a “good point,” explaining some of the potential side effects related to the COVID-19 vaccines. 

“When you get vaccinated, if you get, particularly, the two-dose vaccine, after the second dose, you can sometimes feel fatigued, maybe a little chilly,” Dr. Fauci says. “That’s a good thing, because when your body has that reaction, that means your immune system is revving up and making a really good response against the virus.”

Rodrigo, 18, said she experienced similar symptoms after receiving her second jab, but was “fine in a couple hours” after taking a nap. 

COVID-19 vaccinations are available for Americans 12 years of age and older. Potential side-effects from the two-dose Pfizer and Moderna shots can include fever, chills, headache, muscle soreness and fatigue.

During her visit to the White House earlier this week, Rodrigo addressed the White House press corps from the iconic podium in the James S. Brady Press Briefing Room, saying she was "honored and humbled to be here today to help spread the message about the importance of youth vaccination."

"I am in awe of the work President Biden and Dr. Fauci have done and was happy to help lend my support to this important initiative," she continued. "It's important to have conversations with friends and family members, encouraging all communities to get vaccinated, and actually get to a vaccination site, which you can do more easily than ever before, given how many sites we have and how easy it is to find them at vaccines.gov."

Rodrigo's debut album, "SOUR," was released in May and featured three singles that topped the U.S. Billboard Hot 100 chart – it was the first debut album in history to see two songs ('good 4 u,' 'drivers license') top the Billboard Hot 100 chart, and only the fourth album overall to do so. Only Mariah Carey's "Daydream," Drake's "Scorpion" and Ariana Grande's "Thank U, Next" held the honor, and all three were released later in those artists' careers.

The Associated Press contributed to this report.