The former Good Morning Britain presenter laid into the star for talking about her son in interviews in the lead up to the release of her first album in six years, 30.
He accused Adele of “flogging” eight-year-old Angelo’s privacy – which he noted she’d previously gone to lengths to protect – pointing at the inclusion of audio voice notes from conversations with him about her divorce from his father Simon Konecki on a track entitled My Little Love.
Referencing Adele’s interview with Oprah Winfrey on her US TV special over the weekend, Piers wrote in his MailOnline column: “Has she given a moment’s thought to how Angelo might feel when he grows up to have had his agonising conversations with his sobbing mum about her decision to dump his dad broadcast to the world?
“She’s crossed a line by exposing her young son’s innermost feelings to public scrutiny in such a soul-baring, intimate way.”
“And worse, she’s done it for attention, money, and sales,” Piers continued.
“Sorry, Adele – but I find that shameful, and given all your pleas for privacy, horribly hypocritical.”
However, Piers did insist that he “likes” Adele, calling her a “gutsy, honest young woman with a brilliant voice”.
Piers added: “I’ve no doubt this album will be a massive hit. Indeed, I will buy it myself when it’s released on Friday.”
Earlier this week, Adele faced similar criticism from Loose Women panellist Janet Street Porter.
In a column also for MailOnline, the former tabloid editor called her “deeply shallow” and accused the star of “fake misery”, having “gushing tears on tap every hour” and speaking about her personal life “to shift product”.
Janet wrote: “In the final countdown to Adele’s much-anticipated fourth album, the tidal wave of waffle and wallow shows no sign of receding – Adele is everywhere, telling us about the ‘struggles’ that fired her song writing.”
“Blah blah blah. Anything to shift product,” she scoffed.
“My main beef with Adele is that the more she gushes, the less I love her.”
Over the weekend, Adele showcased four tracks from her highly-anticipated new album, 30, ahead of its official release this Friday, as part of the US TV special.
She has also recorded a UK TV special in front of a star-studded audience at the London Palladium, which is set to air on ITV this Sunday.