"The minute they met each other, it was love at first sight," a friend of the newly engaged couple tells PEOPLE
Demi Lovato and Max Ehrich Engagment
Demi Lovato and Max Ehrich
| Credit: Angelo Kritikos

Demi Lovato's engagement to Max Ehrich after four months was certainly swift, but as the saying goes, "When you know, you know."

In this week's issue of PEOPLE, on newsstands Friday, sources close to the "Sorry Not Sorry" singer, 27, and TV actor, 29, attest that they were serious from the start.

"The minute they met each other, it was love at first sight," says a source close to the couple, who moved in together in March just weeks after meeting.

When the coronavirus lockdown went into effect in mid-March, the pair were brought even closer together as they spent most of their time sheltered at home in Los Angeles.

"They got to know each other really well," says a Lovato friend. "They had talked about getting engaged, but Max kept the proposal a surprise."

Ehrich popped the question on a beach in Malibu on July 22, with a stunning diamond ring crafted by celebrity jeweler Peter Marco. Lovato announced their engagement on Instagram shortly after.

"You never pressure me to be anything other than myself," she captioned a series of photos from the special moment. "And you make me want to be the best version of myself. I'm honored to accept your hand in marriage. I love you more than a caption could express but I'm ecstatic to start a family and life with you. I love you forever my baby. My partner. Here's to our future!!!! 😩😭❤️🥰😍."

Sharing similar images captured by photographer Angelo Kritikos, the former The Young & the Restless actor explained he could not wait a moment longer without having the singer as his wife in his own Instagram post.

"Ahhhh 💍😭🥳💓 You are every love song, every film, every lyric, every poem, everything I could ever dream of and then some in a partner in life," he captioned the set of photographs. "Words cannot express how infinitely in love with you I am forever and always and then some. I cannot spend another second of my time here on Earth without the miracle of having you as my wife. here’s to forever baby."

RELATED VIDEO: Demi Lovato and Boyfriend Max Ehrich Are Engaged: 'I Knew I Loved You the Moment I Met You'

After Lovato said yes, the couple headed to nearby Nobu to celebrate.

"Demi got teary-eyed a few times. She couldn't stop staring at her ring," says an onlooker. "You could tell it was both exciting and overwhelming for her."

Two days after the proposal, Lovato — who was hospitalized after a near-fatal drug overdose in 2018 — reflected on finding peace after hitting rock bottom.

"I can genuinely say I feel free of my demons," Lovato, who’s been open about her mental health and addiction struggles, wrote on social media on the anniversary of her overdose on July 24. "And it’s not just because I fell in love, but because over the past 2 years, I’ve done more work on myself than I have in my entire life."

As Lovato continues focusing on her recovery, she’s found an encouraging partner in Ehrich.

"Max is supportive of her recovery," says the Lovato friend. "Her family and friends are happy for her.”

"Since Demi started seeing Max, it's been obvious she is loving life," adds another insider. "He is a great guy, and it's amazing to see her this happy."

For more on Demi Lovato and Max Ehrich's whirlwind engagement, pick up the latest issue of PEOPLE, on newsstands Friday.