Worlds collided over the weekend as Rebel Wilson and Fergie, Duchess of York attended a wedding together.

The Australian actress and British royal Sarah Ferguson, Duchess of York both travelled to Chelsea in London’s west for the nuptials of Rebel’s “dearest friend” Marissa Montgomery and her partner Jesse Brown.

The pair posed for a photo together alongside Rebel’s fiancée Ramona Agruma and Rebel’s mother Sue Bownds.

Ramona Agruma, Rebel Wilson, Sarah Ferguson (Fergie) and Sue Bownds at a Chelsea wedding (Instagram)

Wearing their wedding best, Dissident wore a dazzling white, flower organized dress with a belt detail while Sarah selected a naval force dress.

Rebel shared the photograph to her Instagram account alongside different pictures from the eagerly awaited day. She subtitled the post with a message of congrats to the love birds.

“The biggest congratulations to my dearest friend Marissa Montgomery who got married yesterday at Chelsea Gardens to the handsome [Jesse Brown],” she wrote.

“We love you! What a gorgeous wedding.”

Ramona Agruma, Rebel Wilson and daughter Royce Lillian at a Chelsea wedding (Instagram)

Other images from the day including a photo of the newlyweds and one of her daughter Royce Lillian, who appeared to be a flower girl.

Despite featuring the photo with Sarah front and center on her Instagram grid, Rebel made no mention of the royal rendezvous.

But fans in the comment section were not so tight-lipped.

“Just casually dropping the pic with Sarah! No biggie!!” one wrote.

“I luv (sic) how Sarah Ferguson is prominently featured in your pic and no mention of her,” wrote another.

Sarah Ferguson (Fergie) hugs bride Marissa Montgomery (Instagram)

Rebel took to her Instagram stories with more photos from the wedding.

One of them was a sweet photo of Sarah appearing emotional as she hugged the bride.

Meanwhile, it was a whole family affair for Rebel who was accompanied by Ramona, Sue and young Royce.

Rebel shared a photo of her family travelling from the big day with the caption: “My cuties.”

It also appeared to be a quick trip for Wilson who shared a photo of Royce from inside a jet on the way to their next location.