Lovato turns 27 on Aug. 20

Demi Lovato is kicking off her birthday week in London!

On Monday, Lovato — who turns 27 on Aug. 20 — shared a sweet video of her gal pal Ariana Grande leading a birthday chant in Lovato’s honor (as it’s already Tuesday in the UK) ahead of the “thank u, next” singer’s concert at the London O2 Arena.

“This was too sweet not to post… before show prayer they did this for my bday,” Lovato captioned the clip, which shows Grande, 26, and her crew, as well as their shared manager Scooter Braun, cheering.”I’m so proud of you @arianagrande. You f—ing killed that!! I love you tons 💕.”

The pair also shared a warm embrace in the clip before Grande hit the stage.

Lovato’s 27th birthday comes a year after her near-fatal overdose.

A source tells PEOPLE, “Demi is in a great place in her life. She is spending her birthday in London and working on new music and other projects.”

Ariana Grande Instagram
Ariana Grande and Demi Lovato
| Credit: Ariana Grande Instagram
Ariana Grande
Demi Lovato and Ariana Grande
| Credit: Ariana Grande Instagram

The star also remains committed to her health. The source adds that Lovato is still practicing jiu-jitsu. “She’s healthy and has been working out.”

Just before Grande’s show, Lovato also posted a mirror selfie of herself, captioning it, “Last day as 26 🖤.”

The star looked concert-ready in a white crop top paired with a leather jacket and narrow-framed black sunglasses.

The birthday celebration didn’t end there. Lovato followed up with a final post, which shows her blowing out candles atop a birthday cake.

“Okay, last one before bed,” Lovato wrote.

“They literally filmed/sang happy birthday twice and @scooterbraun STILL forgot to press record 😂 @arianagrande’s face is everything,” Lovato said of Grande, who was visibly agitated.

“This video is a perfect glimpse of how f—ing happy and rad my birthday is this year. So so happy. and I love my new family. Thank you guys, love you 🙏🏼🙌🏼.”

Following a tough year, Lovato has been keeping a close-knit circle of family and friends around her.

“Demi is very close to her family,” a source previously told PEOPLE. “She often stays at her mom [Dianna De La Garza’s]. She attended [Madison’s] high school graduation in June. Spending time with her family always seems very important to her.”

“[She] is surrounding herself with a small group of friends,” the source continued. “You can tell that everyone is very protective of her.”

Demi Lovato
Demi Lovato
| Credit: Demi Lovato Instagram

The entertainer, who has battled addiction, mental illness and eating disorders for years, first broke her silence after her overdose on social media on Aug. 5, 2018 when she shared an update on her health following her hospitalization.

“I have always been transparent about my journey with addiction. What I’ve learned is that this illness is not something that disappears or fades with time. It is something I must continue to overcome and have not done yet,” Lovato wrote. “I want to thank God for keeping me alive and well,” she added, before praising her fans for standing by her through the difficult time.

Lovato concluded, “I now need time to heal and focus on my sobriety and road to recovery. The love you have all shown me will never be forgotten and I look forward to the day where I can say I came out on the other side. I will keep fighting.”

Demi Lovato
Demi Lovato
| Credit: Ari Perilstein/Getty Images

She remained in a treatment facility until November, when she checked out and then began splitting time between her mom De La Garza’s home and a sober living facility.

In February, reports began circulating that Lovato had relapsed and re-entered a treatment facility.

A source close to the singer, however, told PEOPLE exclusively at the time that the rumors were not true, but confirmed that Lovato did choose to check into a treatment facility on her own to continue working on her health.

If you or someone you know is in need of help, please contact the SAMHSA substance abuse helpline at 1-800-662-HELP.

If you or someone you know is battling an eating disorder, please contact the National Eating Disorders Association (NEDA) at 1-800-931-2237 or go to NationalEatingDisorders.org.