Tesla chief Elon Musk has responded to reports that he and Shivon Zilis, a top employee at his brain chip startup Neuralink, had twins in November 2021.

Taking to Twitter, Mr Musk said that he is doing his “best to help the underpopulation crisis.” He even added that a “collapsing birth rate is the biggest danger civilisation faces by far.”

Business Insider had reported that Elon Musk had twins last year with one of his top employee. The report stated that in April, Mr Musk and Ms Zilis filed a petition to change the name of the twins to “have their father's last name” and contain their mother's last name as part of their middle name.

The outlet also said that a court docket summary on the Westlaw legal research service showed a judge signed an "Order Changing the Names Of Multiple Children" on May 11 after the name change petition from Mr Musk and Ms Zilis made on April 25 this year.

Now, the news of the twins brings Elon Musk's total count of children to nine. The Tesla and SpaceX CEO has five children - Griffin, Vivian, Kai, Saxon and Damian - with Candian author Justine Wilson.

Elon Musk also has two kids - X AE A-XI and Exa Dark Sideræl - with singer Grimes. The names of the twins are yet to be known.