A woman gave birth in front of festivalgoers during Notting Hill Carnival yesterday.
Emergency crews rushed to reports of a person in labour at roughly 6.45pm and took them to hospital "as a priority".
Footage shared to social media shows four police officers assisting the woman as she laid on the pavement, reports MyLondon.
A woman says "she's having a baby" as crowds gather nearby and cheers are heard in the background.
It is not known whether the woman who gave birth was attending the carnival at the time.
A London Ambulance Spokesperson said: "We were called at 6.45pm on Sunday, August 28, to reports of a person in labour within the footprint of Notting Hill Carnival.
"We treated an adult and baby at the scene and took them to hospital as a priority."
Notting Hill Carnival has been online in recent years due to the Covid-19 pandemic, but made an in-person comeback yesterday.
Millions are expected to attend over the course of the two-day festival.
As huge crowds gathered on day one, two people were injured when a bus shelter collapsed in the Ladbroke Grove area.
Several people were seen standing and dancing on top of it before the incident, with those watching heard to gasp and exclaim in shock as the group fell through the top of the shelter.
The two people affected suffered minor injuries and did not need further treatment, police said.
Elsewhere, Carina Charles, 40, a nurse from Basildon, said: "I like the togetherness of the people and the mixture of the culture.
"My Caribbean music, the soca music is what I love the most."
She added: "Everybody is jovial - they are excited after coming out of lockdown after three years."
Different sound systems dotted around the streets of west London entertained the dancing crowds as revellers smiled to the booming music.
Small children standing on the doorsteps of their houses waved Jamaican flags and waved at passers-by.
Shauna Walsh, 38, who lives in Kensal Rise, said: "The atmosphere has been really uplifting and warming - it is nice to be back."
London mayor Sadiq Khan said: "As a Londoner I'm really pleased carnival is back."
He said carnival was celebrating Caribbean culture, heritage, and history and there was a "pent up" demand for festivities this year.
He added: "We think it's going to be the biggest and best ever."
But Mr Khan also warned the cost-of-living crisis had affected the carnival.
He said: "We are seeing those who want to have floats, those who want to have sound systems, pulling out because they can't afford to pay their bills."
