Director Olivia Wilde praises Harry Styles for playing supporting role in Don't Worry Darling

Olivia Wilde has expressed her gratitude for boyfriend Harry Styles as they wrap up filming Don't Worry Darling.

The 36-year-old director praised the 'Golden' singer for playing a supporting male role "to allow for a woman to hold the spotlight."

"Little known fact: most male actors don't want to play supporting roles in female-led films," she captioned her Instagram post. "The industry has raised them to believe it lessens their power (i.e financial value) to accept these roles, which is one of the reasons it's so hard to get financing for movies focusing on female stories.

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"Enter: @harrystyles, our 'Jack'. Not only did he relish the opportunity to allow for the brilliant @florencepugh to hold center stage as our 'Alice', but he infused every scene with a nuanced sense of humanity. He didn't have to join our circus, but he jumped on board with humility and grace, and blew us away every day with his talent, warmth, and ability to drive backwards."

The pair are believed to have fallen for each other during production. Her post comes just weeks after she was spotted holding Styles' hand at his manager's wedding in January.

Wilde revealed Styles joined the cast after she fired Shia LaBeouf from the role. In conversation with fellow filmmaker Emerald Fennell, she revealed she has a "strict no a--holes policy" on set.

"It puts everybody on the same level," she explained. "I also noticed as an actress for years how the hierarchy of the set separated the actors from the crew in this very strange way that serves no one."

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According to Variety, LaBeouf "exhibited poor behaviour and his style clashed with the cast and crew, including Wilde, who ultimately fired him."