The purchase, led by former Disney executives Kevin Mayer and Tom Staggs, values Witherspoon’s Hello Sunshine at about $900 million, according to a person with knowledge of the matter who asked not to be identified.

Witherspoon and Hello Sunshine’s senior management team, led by Chief Executive Officer Sarah Harden, will continue to oversee its day-to-day operations and hold “significant” equity in the business, according to a statement Monday. Witherspoon and Harden will also join the new media company’s board.

“This deal enables Hello Sunshine to accelerate its already strong growth, while also remaining independent,” the parties said.

Blackstone has been building a media and entertainment portfolio through its private equity business, which previously acquired a majority stake in the dating platform Bumble.

It’s also buying up real estate used for film and TV production and announced a deal Monday to spend $974 million to build a film studio north of London with Los Angeles-based studio operator Hudson Pacific.

The Hello Sunshine agreement marks the first investment for Mayer and Staggs’ new Blackstone-backed media company.

The fast growth of streaming has led to a surge in film and TV deals as major companies look to bolster their libraries and others position themselves to supply programming to top players. Amazon.com Inc. agreed in May to buy Metro-Goldwyn-Mayer for $8.45 billion, providing content and production capabilities for its online video business.

Hello Sunshine is owned by Witherspoon and her partners, Seth Rodsky and Jim Toth. Toth is a former talent agent with Creative Artists Agency and is Witherspoon’s husband. Blackstone is spending about $500 million to acquire shares from existing investors, according to the Wall Street Journal, which reported on the deal earlier Monday.

Hello Sunshine has produced shows like the HBO drama “Big Little Lies” and the Apple TV+ series “The Morning Show.” It’s also the home of Witherspoon’s book club.