A tweet from her personal account an hour ago reads, “Before Amanda Bynes…” – a reference to the controversial American starlet who suffered a very public meltdown recently – “there was…”

The message then links to a collage (see above) of O’Connor’s tweets in which she refers to her own mental health issues.

Among those springing to Sinéad’s online defence are Hot Press scribe Emma O’Brien whose tweet to Cyrus reads: “So you love her and she offered some sage advice and now you're exploiting her mental illness? Way to go you should be SO proud.”

Meanwhile, celebrity blogger Perez Hilton observes: “It is never okay to poke fun at mental health. Ever.”