Shania Twain spent her birthday weekend doing what she loves most — performing on stage.

The singer turned 59 years old on Wednesday (Aug. 28), and during her Las Vegas residency date scheduled for the following night, she held a mini-birthday celebration onstage, treating fans to a surprise appearance from legendary R&B group Boyz II Men.

But what Twain didn’t see coming was that the group was planning a special surprise of their own.

The two acts gave a duet rendition of Twain’s late-’90s hit “You’re Still the One,” followed by an a capella performance of Boyz II Men’s classic “I’ll Make Love to You.” As far as Twain was concerned, that was supposed to be the end of the surprise — but as she began to thank them for joining her onstage, they said, “One more thing,” and broke out into a rendition of “Happy Birthday.”

Twain was so busy watching their performance — and “cha cha cha”-ing along — that she didn’t at first see her husband, Frédéric Thiébaud, wheeling out a towering pink cake onto the stage behind her.

“Happy birthday. We truly appreciate you inviting us onto your beautiful stage,” the vocal group told Twain as she came up to thank with a hug.

“Would you believe I hate being the centre of attention considering my career?!” Twain joked in the caption of a social media post she shared to document the moment. “Thank you to my husband [Frédéric Thiébaud], Boyz II Men, my awesome crew, everyone at [Planet Hollywood] and of course to my beautiful fans for celebrating with me. I’m feeling very loved.”

To celebrate his country superstar wife’s birthday, Thiébaud also posted a snapshot of them sitting on a boat together last week, writing “Happy birthday to this amazing human being.”

Twain is currently in the midst of her Shania Twain: Come on Over — The Las Vegas Residency — All the Hits! show, which is set to continue into mid-December.

Carena Liptak is an Associate Editor and staff writer at Taste of Country. She specializes in breaking country music news, interviews and lists. In particular, she’s got a soft spot for sad songs — check out her roundup of the 50 Saddest Country Songs of All Time!