"Mom's Last Chemo Day!! BEAT IT!!!" Julia Louis-Dreyfus' sons wrote in a video shared to Instagram Thursday

Julia Louis-Dreyfus and her sons have reason to celebrate — it’s the Veep actress’ last day of chemotherapy treatment!

Louis-Dreyfus, who was diagnosed with breast cancer in September, completed her last round of chemo Thursday, and in celebration of the monumental day, her sons — she shares Charlie, 20, and Henry, 25, with husband Brad Hall — extended their support in a sweet (and hilarious) way.

The brothers sent their mom a video of themselves lip-syncing the words to Michael Jackson’s “Beat It” — complete with hand motions and passionate facial expressions — which she shared on Instagram with her followers.

“Mom’s Last Chemo Day!! BEAT IT!!! Love, Henry and Charlie,” overlaid text at the beginning of the footage reads.

“My beauty boys @henryhallmusic @charlie_hall made this for me today, my last day of chemotherapy,” Louis-Dreyfus, 56, captioned the video. “Pretty swell, right? Ain’t they sweet?”

Louis-Dreyfus revealed her diagnosis days after she won her sixth consecutive outstanding lead actress Emmy for her role as Selina Meyer on Veep, setting the record for most wins for a performance in the same role for the same series. (She is also nominated for a Screen Actor’s Guild Award for outstanding performance by a female actor in a comedy series at the ceremony Jan. 21.)

“1 in 8 women get breast cancer. Today, I’m the one,” she tweeted at the time. “The good news is that I have the most glorious group of supportive and caring friends, and fantastic insurance through my union.”

Continued Louis-Dreyfus, who has remained positive on social media throughout her battle: “The bad news is that not all women are so lucky, so let’s fight all cancers and make universal health care a reality.”

After her announcemet, her sons both took to social media to thank fans for their kind words.

“I couldn’t be more thankful for the outpouring of support for my mom yesterday,” Henry wrote.

“The support for my mom these last couple days has been so awesome. Much love to everyone,” Charlie wrote. “Also, my mom rules.”

HBO told PEOPLE that Louis-Dreyfus learned of her diagnosis one day after the Sept. 17 award show, noting that “it in no way impacted the decision to make this the final season” and that the production schedule will be adjusted as needed. In November, the HBO series’ executive producer Frank Rich confirmed that production had been postponed.

“Julia is undergoing treatment for breast cancer, and we’re obviously postponing production of the show — we were supposed to have started now – while she’s in treatment,” he said during an interview with SiriusXM’s Press Pool. “But the expectation is that we will shoot again. We have one more season we’re doing, which we’re incredibly excited about. Rather impressively, while we wait for her to gather her full strength, around her treatment, we’ve been having with the cast in Los Angeles, table reads of scripts for the final season as they’re ready.”

“So it’s been quite something because she’s fighting a serious, what is for anybody, a real illness. And yet, wants to keep working as much as circumstances allow without being crazy about it,” he shared.

He added: “I’ve seen her as recently as 10 days ago, and watched her just be hilarious playing Selina Meyer. With the cast all around her playing the assorted group of idiots that Selena has to deal with on a weekly basis on the show. So she’s got a great support system. She’s a very strong person and we can’t wait to welcome her back at full speed.”