Olivia Wilde takes 'breast milk' ice bucket challenge

The actress poured the milky-looking fluid over her head following a number of nominations

Olivia Wilde has completed her ice bucket challenge - with "breast milk" (Twitter/Olivia Wilde)

Olivia Wilde has seemingly (not) upped the ante for the ice bucket challenge, throwing what she – with a dead pan expression – says, is a whole load of breast milk.

On a stunning rooftop balcony, she lobs what she says is a bucket of breast milk over her, after she “couldn’t find any water” and which had taken her “all night to make”.

Wilde, who gave birth to a baby boy in April, later clarified the stunt and confirmed that it wasn’t in fact breast milk.

She was nominated by Glee star Dianna Agron and child actor Ty Simpkins among others, and decided to pass on the challenge to Senator Cory Booker, writer Gloria Steinem, and ambitiously, The Artist Formerly Known as Prince.

“Oh wait some of you thought that was really breast milk? Oh dear. Uh thank you? But my boobs aren't that generous. Haha,” she tweeted.

Many people who weren't aware of the trick were confused, with some responding that her newborn son Otis will be sad to lose the food, while others congratulated her.

The star is a vocal supporter of breastfeeding and has recently been beautifully snapped feeding her son in a photoshoot for the September issue of Glamour magazine.