Daisy Lowe, who has been friends with Peaches since childhood, tweeted a picture of a broken heart on Monday, as news of the 25-year-old's death surfaced.
She has remained silent on social media ever since.
Currently staying in Los Angeles with her father, Daisy was taken out for lunch by the rock star - perhaps in a bid to take her mind of the tragedy.
The pair appeared to be having an intense discussion as they dined out in Hollywood together.
Daisy only discovered that Gavin Rossdale was her father at the age of 14, after requesting a paternity test. The result led to Gavin refusing to speak to her mother, Pearl Lowe.
Rossdale has been married to No Doubt frontwoman Gwen Stefani since 2002, and the couple welcomed their third child together at the end of February - though the baby is yet to be pictured out in public.
Peaches' death has caused many celebrities to pay tribute to the star, who seems to be universally referred to as funny and sweet. Her father, Bob Geldof, expessed his grief on Monday, saying that: 'We are beyond pain. She was the wildest, funnies, cleverest and most bonkers of us all.'
Her Post-mortem proved inconclusive yesterday and the family must now wait for toxicology reports.