The pews fill up with grinning faces, outlandish costumes, and, of course, red noses.
The sermon, punctuated by quips and one-liners, features a special prayer: "Dear Lord, thank you for calling me to share your precious gift of laughter."
This is not a typical service, nor a place for those suffering from coulrophobia
For the last 70 years, clowns have lined the pews of an east London church in tribute to their late master, Joseph Grimaldi.
Regarded as the father of the modern-day clown, Grimaldi transformed the role and appearance of the comic performer in the 18th century, delighting audiences, including Charles Dickens.
The celebratory occasion is a departure from the creepy clown craze in the US and the UK
around Halloween last year, which for the clown community, was no laughing matter.
Mr. Woo, a 78-year-old clown, says he lost three bookings because of the trend.
"For the first time ever, I was going to work with no clown-face on because they said 'please don't come as a clown because my child will be frightened,'" he says.
"Being nasty and scaring people isn't what we're about at all" says a clown called Zaz, before readjusting the red nose on his four-year-old son Isaac.
But the clowns refuse to let the creepy craze put a dampener on their day. Instead, they reflect on gifts that clowns, like Grimaldi, have bestowed upon them.
MC Mattie the Clown, concludes the service with a nod to another famous laugh maker.
"Clowns are the catalyst to laughter," she says. "And as Charlie Chaplin said: 'A day without laughter is a day wasted.'"