girls aloud
The singer and actor said Sarah's "infectious chuckle" was “one of my favourite things in the world”.
Sarah's fearlessness, shining personality and, of course, talent helped propel Girls Aloud to stardom.
The singer's death was announced on Sunday by her mother.
Geri Horner and Davina McCall – who met Sarah back in her Popstars: The Rivals days – are among those to pay their respects.
The chart-topping star revealed last year that she'd been diagnosed with breast cancer.
The singer celebrated turning 38 with her bestie and former bandmate, Kimberley Walsh.
The Girls Aloud star says she was given "a little bit of positive news" at the end of last year.
The Girls Aloud star also told of how she spent nearly two weeks in an induced coma with sepsis.
“Thank you for the love and support, on bad days it helps me so much,” the Girls Aloud star tweeted.
The Girls Aloud star posted a short clip on Snapchat a month after revealing she'd been diagnosed with cancer.