Jessica Simpson believes snake sperm has improved her singing.

The 44-year-old singer-and-actress' vocal coach recommended she started drinking a "Chinese herb thing" and she revealed the special beverage has some very unconventional ingredients - but she thinks she's experiencing the benefits.

In a video shared to Instagram, in which Jessica drank the solution in front of her band, she said: "They're like, 'What are you drinking?' Because it's this Chinese herb thing.

"And I'm like, 'I don't know.' My vocal coach told me to drink it, and they Googled the ingredients and - snake sperm. It's like a honey.

"So, if you want a good vocal, you gotta drink snake sperm."

The 'Dukes of Hazard' star captioned the post with three emojis depicting the drink, a microphone, a snake and a test tube containing a green substance.

Jessica - who has Maxwell, 12, Ace, 11, and five-year-old Birdie with estranged husband Eric Johnson - has been sober since 2017 and recently credited giving up alcohol for helping her reconnect with music.

She told People magazine: "The moment I started drinking too much was when I started writing music in 2016 and it was making me go to places and feel sorry for myself.

"I don't know why I wanted to feel sorry for myself other than the alcohol was lying to me and saying, 'You're braver because you can say this with me on your side.'"

And after being seven years sober, Jessica believes she is now much more "honest" and confident in herself.

She added: "I actually am so much more honest without alcohol, and I actually believe myself so much more without alcohol.

"[Drinking] made my emotions quiet. Instead of addressing them, dealing with them and getting through it, I was just letting them be".

Reflecting on her early career, Jessica said she struggled to assert herself within the music industry.

She added: "You have a lot of people pushing and pulling at you, and putting money into you, and you say 'Yes'.

"I'm obedient. I'm a preacher's daughter. I didn't stand up for myself. I had a big voice but I didn't have a voice that people would listen to when I would speak."