Denise Welch said she "lost the ability" to love her first son Matty Healy, due to her battle with postnatal depression.
Matty, who is the frontman of one of this year's Glastonbury headliners The 1975, is the eldest of Denise's two sons with her ex-husband Tim Healy.
Speaking on the Loose Women podcast, the panellist recalled being "the typical blooming mum" during pregnancy who was not anxious about having a baby, until her mental health took a turn.
Denise said while she "immediately" bonded with Matty, now 35, after a difficult 42-hour labour, she lost control of her emotions five days into being a mother.
The 66-year-old explained: "I was going through the emotions of smiling, and I went to bed that night and I had the first panic attack I'd ever had in my entire life, from nowhere. It wasn't because I was anxious, it was from nowhere.
"When I got up from maybe a two-hour sleep, I had gone to bed with full breastfeeding boobs, and I woke up with Spaniel's ears.
"All of my milk had gone, the whole lactation process had stopped and the depression set in."
Denise describes that feeling at the time as "blackness" which "rose from the bottom" and she was later told she was "between postnatal depression and puerperal psychosis".
"So I was in and out of lucidity as to, who is this child?", she continued.
At one point, the Loose Women star said her mother had found her trying to crawl out of the window in the lounge, which was followed by a visit from medics.
Because of her illness, Denise "lost the ability to love" Matty, adding: "I couldn't love anything, I felt nothing."
The actress went on to praise her "incredible" mum who encouraged her to prepare the bottles for Matty and feed him when needed, in a bid to get her to bond with him.
"She knew that he needed feeding every four hours, and I had no natural inclination to pick up this child," she explained.
"I didn't hate the child, I didn't want anything to happen to it, it was just like, why is this child here?"
Denise said she began to see "light at the end of the tunnel" once prescribed medication for what she calls the "unwelcome visitor", and admits to still having good and bad days.
Reflecting on the pair's current bond now, she added: "I'm so lucky that we are, you know, Matty and I have a great relationship. It's so nice considering the start of it."
The singer has since written a song about his mum's depression titled She Lays Down, based on his adult view of her illness.
With his band, Matty will be bringing their greatest hits to the stage as one of the headliners at this year's Glastonbury.
Announced on Thursday, other artists taking to the stage in June include Neil Young, Olivia Rodrigo and the legend Sir Rod Stewart.
