Hilary Duff is "great at being a supportive listener", according to sister Haylie.
Both siblings are mothers - Hilary has three-year-old son Luca, while Haylie welcomed daughter Ryan last year.
And they make it their missions in life to be there for each other, through hard times and good.
Haylie said: "We really don't push advice on each other anymore. We really focus on just being there for each other.
"In the first few weeks of having Ryan, when I would be so exhausted or I didn't know what to do, she would just come and be at the house and just help me. She would just hold [Ryan] if she needed to or just swaddle her if she needed to."
The fact that Hilary was already an experienced parent meant Haylie could relax slightly and seek advice from her sister when she needed to.
She added to Celebuzz.com: "I think just being there and being supportive without pushing your way on other moms or new moms is the best thing that you can do.
"We don't really give each other advice when it comes to stuff like that. We try to just support how the other feels. If I ask her for advice, she would tell me, but she's just really great at being a really supportive listener too."