HOLLY Willoughby pulled out of presenting This Morning shortly before it aired after learning of an alleged plot to kidnap her.
The star presenter was under police guard at her home last night after the horrific ordeal.
It comes as a 36-year-old man was arrested on Wednesday night by police who allegedly found “sinister messages” threatening to kidnap and “seriously harm” the mother-of-three.
The man, who was unknown to the star, was in police custody last night.
Police alerted This Morning executives to the alleged plot early yesterday.
Holly was informed shortly before it was scheduled to air.
She was “shocked and distraught” and it was decided that she should withdraw from the show.
Alison Hammond was brought in as a last-minute replacement alongside Josie Gibson, who co-hosted Wednesday’s show with Holly.
Viewers were stunned as Josie skirted around her absence, saying: “Look who has joined me.
“It’s just the one and only Alison Hammond.”
Alison then joked about being “jealous” of her and Holly.
One fan wrote: “No Holly today?! Devastated.”
Another added: “Didn’t even mention why she wasn’t there today?!”
It was unclear how police became aware of the alleged plot, but it was understood digital devices and a mobile phone were seized.
Police guards are stationed outside around the clock while investigators continue their investigation Holly’s London homewhere she lives with her husband and children.
A source said: “Investigations are ongoing but police are treating this as a credible conspiracy to kidnap Holly.
“It appears some sinister and threatening messages were found on electronic devices that threatened to cause her serious harm.”
Holly was due to celebrate her husband, TV producer Daniel Baldwin’s 49th birthday with her children Harry, 14, Belle, 12, and eight-year-old Chester.
The incident comes after a turbulent year for the star, who has hosted This Morning since 2009.
Last September she and then co-host Phillip Schofield were accused of skipping the queue to pay their respects to the late Queen.
She later issued a statement saying she was there as an accredited presenter for a filmed portion.
Holly added: “Please know that we would never join a queue.”
In May this year, Schofield, 61, resigned after admitting an affair with a younger colleague.
Schofield also revealed that he lied about it when he confronted Holly.