Katy Perry was "panting like a dog" while her sister was in labour.
The Dark Horse singer's older sister Angela gave birth to a daughter in her friend's living room back in March.
Self-titled "pop star and child deliverer" Katy was on hand to go through every moment with her sibling.
"I'm an assistant doula, that's what they called me the whole time," the 29-year-old told Jimmy Kimmel Live.
"We had a midwife and there was a tub in the living room, I was holding a leg, and panting like a dog. Like, primal noises coming out."
A doula is a non-medical person who assists during labour. When Katy wasn't cradling her sister's limbs or doing her own heavy breathing, she revealed that she filmed a lot of the process.
"[Angela] decided to go the all-natural way, not a single aspirin," she told the host proudly. "I mean, I don't know how that feels, everything I saw - 'cause I was Scorsese-ing up in there with my video camera, just covering anniversaries and birthdays, y'know what I'm saying - but it was amazing."
Katy, who also has a younger brother David, is close to her siblings and has even included a nostalgic photograph with Angela on the artwork of her new single, Birthday.
In the shot, the two little girls are seen at a party with big bows in their hair. When questioned by Jimmy if she asks her sister's permission before using her image on social media, Katy joked, "Mainly forgiveness!"
While Katy loves being an aunty, she isn't ready for motherhood just yet. She previously revealed to Marie Claire that it was one of the main reasons her marriage to Russell Brand ended in December 2011.
- Cover Media