Solange Knowles has spoken out in praise of her sister Beyoncé's work ethic.

The 'Drunk In Love' star gave birth to her first child Blue Ivy in 2012, but she has been out around the world on tour over the last year.

Speaking to ASOS, sister Solange said that Beyoncé's ability to juggle work, parenthood and play is "insane".

She said: "I have never seen anything like it in my life, from anyone. It's absolutely insane.

"Now that she's become a mother, and the way that she's able to balance that is so inspiring, If I am ever feeling like I want to open up my mouth and complain about how hard I am working, I think, 'Uhhh! Sit down!'."

Solange meanwhile has one child - Daniel Julez J. Smith Jr, who was born in 2004.

Watch Beyoncé dance with Solange at Coachella 2014 below: