Frankie Bridge told her husband to write a will while they were on the plane heading off on their honeymoon.
The 32-year-old star said she suffered an anxiety attack after jetting off on the break with footballer husband Wayne in 2014, leaving their nine-month-old son Parker behind.
Bridge reveals in her new self-help book — reported via the Mirror — that she "burst into tears" on the flight and begged Wayne to contact a lawyer while on the plane.
She wrote: "I had tried to overcome the sense of terror and fear that engulfed me throughout the days leading up to this moment and suddenly, when I realised I couldn’t turn back, I was here, on a plane with no exit, it hit me.
“At a time that we were supposed to be at our happiest, I realised that if we both died Parker would be alone and without parents for the rest of his life."
Bridge said this brought about a "crisis moment" for her when she realised that there was no plan in place for Parker's care if anything did happen to them.
She added: "This type of crisis moment is something I had dealt with throughout my life, but I had never been responsible for someone else and this compounded my paranoia and exacerbated my fears."
Bridge has spoken openly about her battles with anxiety and depression and works as an ambassador for the mental health charity Mind.
Her new book, Grow: Motherhood, Mental Health and Me, features her speaking frankly about her struggles over the years and the ways in which she has learned to cope.
Watch: Frankie Bridge reminds fans to keep up with prescriptions
Bridge makes numerous admissions about her mental health in the book, including her fears that she had killed Parker when she was told he had received his chickenpox vaccine too early.
She wrote: "The guilt and fear I had felt throughout the day spiralled. And it resulted in a complete meltdown.
“My paranoia kicked into overdrive too and I became convinced I had killed my child, before he’d even really got the chance to live.”
The singer and presenter also reveals that her "biggest fear" is that her children — Parker, now seven, and Carter, aged six — will inherit her mental health issues.
She said: "I want them to know that boys can and should cry, that they should talk about their feelings and worries, that there is nothing to be embarrassed about when airing your worries and that it actually only makes you a better person for doing it.”
Bridge began her career as a member of the band S Club Juniors before securing several major hits as part of The Saturdays.
She has been working on solo material since the latter group went on hiatus in 2014.
In 2020, Bridge joined the roster of regular contributors on daytime panel discussion show Loose Women.
Grow: Motherhood, Mental Health and Me is available now, having been released earlier this month.
Watch: Frankie Bridge opens up about anxiety for World Mental Health Day