Kelly Clarkson is said to be putting her children first as she grieves over the death of her ex-husband Brandon Blackstock

A source has now told UsWeekly about how she is dealing wit the fallout from his death from cancer: "It has been draining, exhausting, emotional (and) devastating.

"(But) her children have always come first.

"A big part of (her care for Brandon) was making her schedule available for transporting the children to visit Brandon."

Brandon, a former music manager turned full-time rancher living in Montana, died peacefully surrounded by family on 7 August, after more than three years fighting cancer.

The source also told UsWeekly Kelly's recent hiatus from her The Kelly Clarkson Show and postponement of her Las Vegas residency concerts was driven by her commitment to care for Brandon and their children.

They added: "Kelly is a workhorse. Hard work is all she knows. She hates disappointing people, truly. The thing that kept her going was knowing how many people depend on her, like her crews and employees."

Kelly's NBC show is expected to return this autumn, sources told TMZ.

Clarkson has found support among family and friends during her difficult time but is said to be remaining the central figure for her children, the source added to UsWeekly.

They said: "She has family and friends, but at the end of the day, it's all on her,"

Brandon is survived by his parents, three siblings, four children - including Savannah, his now-pregnant daughter from a previous marriage who is expecting her second child - and grandchildren.

What is thought to be the final photo of Brandon, posted on Savannah's Facebook, showed him smiling alongside her.

A family spokesperson said in a statement about his passing: "Brandon bravely battled cancer for more than three years. He passed away peacefully and was surrounded by family.

"We thank you for your thoughts and prayers and ask everyone to respect the family's privacy during this very difficult time."