The Girls Aloud star spoke out in defence of her bandmate, who has not made a public appearance since being axed from The X Factor USA last month.
"It's kind of weird how people just won't leave Cheryl alone," Walsh wrote in her OK magazine column. "It's relentless and we're all bored of it.
"It's also really frustrating to hear so many fabrications and complete lies written about her, and especially about her mum Joan, too, as she is the most harmless person ever and she never interferes in Cheryl's personal or professional life."
She added: "Some people form an opinion about things they have no idea about. Cheryl has plenty of friends and family around her. She's very happy and I love her lots."
Walsh previously defended Cole's replacement on the American judging panel, Nicole Scherzinger, over claims that she had made a dig at the 'Promise This' star with a recent choice of outfit.
Cole has allegedly taken out an injunction against the paparazzi, preventing photographs of her being taken in private places.
> Cheryl Cole breaks silence over 'X Factor' drama
> Cheryl Cole "fine" after 'X Factor' axe, says Walsh
Watch the video for Girls Aloud's 'Biology' below: