Kate Hudson has revealed that her new song Live Forever is a "love letter" to fellow parents.

On Thursday, the actress/singer released a new song called Live Forever and an accompanying music video made up of home videos featuring her first-born child, Ryder.

"Depending on how you listen, it could be a song of first love, young love, because it has the element of being barely an adult. If that's how it is for you, I love that," Kate, 44, said in a press release. "But for me, it's about the absolutely consuming joy Ryder was for me from the moment he arrived."

Kate shares Ryder, 20, with ex-husband Chris Robinson. She also has a son, Bingham, 12, with ex-fiancé Matt Bellamy and a daughter, Rani, five, with fiancé Danny Fujikawa.

The Almost Famous star continued in the release, "Nothing can prepare you for a love that swallows you whole, but that's what watching my son grow up has been for me - and when we started writing these songs, it was a feeling that absolutely had to be part of the record."

The touching music video consists of a series of clips of Kate and Ryder from the day he was born to the day he grew up and left home.

The Fool's Gold star also took to Instagram on Thursday to explain the meaning behind her new song.

"Our babies leave us eventually and we have to watch them go take on the world. Some of us were so young that we were trying to figure out who we were simultaneously. That's this song for me," Kate wrote. "My love letter to parents and the kids waving goodbye."

She continued, "And all those young mamas out there doing the best they can and trying to do some growing up themselves. You got this. This love will always Live Forever."

Kate released her debut single Talk About Love in January. She is due to release her debut album later this year.