Hilaria Baldwin has laughed off rumours suggesting she's not the biological mother of her children with Alec Baldwin.

The yoga instructor and TV personality shared a laughing emoji along with a photo of herself and baby daughter Lucia on her Instagram Story on Wednesday to address the claims.

"I know... I know, sleuths... my skin is darker and my kids' is lighter," she shared. "Yes, they are mine. Trying to keep up with all these ideas... I have to say: you have quite a bit of time on your hands."

Lucia was born via a surrogate earlier this year, while Hilaria gave birth to the rest of her kids with Alec - seven-year-old Carmen, six-year-old Rafael, four-year-old Leonardo, three-year-old Romeo, and 10-month-old Eduardo.

This isn't the first time Hilaria has taken to social media to address speculation about her private life.

After sparking controversy by speaking with a Spanish accent and claiming "Spanish heritage" despite having been born in Boston, Massachusetts, Hilaria, who was born Hillary Hayward-Thomas, later explained via Instagram last year: "My parents and sibling live in Spain and I chose to live here, in the USA. We celebrate both cultures in our home - Alec and I are raising our children bilingual, just as I was raised. This is very important to me. I understand that my story is a little different, but it is mine, and I'm very proud of it (sic)."

The star, who went on to lose brand partnership deals following the controversy, shared this update in February: "I've spent the last month listening, reflecting, and asking myself how I can learn and grow... The way I've spoken about myself and my deep connection to two cultures could have been better explained. I should have been more clear and I'm sorry."