Lottie and Louis lost their mother Johannah Deakin in 2016 after a battle with leukaemia.
Their little sister Félicité then tragically died in March 2019 from a suspected heart attack after she collapsed in her West London apartment.
Speaking to Lorraine Kelly on Monday about the tumultuous period, Lottie revealed that seeking support “made such a difference”.
“I was able to deal with it a lot better with my sister as I had kind of been through it and picked up a few good coping mechanisms,” Lottie said.
“But I also got extra help when my sister died rather than I did when my mum died, which made such a difference.”
Lottie said her mother was the “sweetest, kindest woman”.
“She was the best,” she said. “She just made our whole life about us, she did everything for us.”
Lottie said she wanted to use her experience to help others have support when dealing with grief.
“That’s why I want to bring awareness like what Sue Ryder does and to let people know that you can get help,” she said, referring to the bereavement charity started by the late actress.
“It does really help with the grieving process to go and see someone and to go and talk to someone.”
Sue Ryder offers care and support for people living with terminal illnesses and neurological conditions, as well as for individuals dealing with the loss of a loved one.