The former BBC Breakfast star has said he hopes the ITV daytime show survives after Phillip Schofield quit following his confession that he had lied to executives about a secret affair with a much younger man.
Walker, 46, told the Mail Online: "The last few weeks must have been awful for Holly so I hope she’s okay and that she learns from it and is a better person because of it.
"It will be interesting to see where they both are in a year’s time."
He said of This Morning: "I believe it’s filled with brilliant, creative, clever people who are making programmes with the right integrity. This Morning is part of the fabric of British TV so I hope it doesn’t disappear."
Willoughby, 42, worked with Schofield, 61, for 13 years on This Morning.
Following his departure from the show after admitting he had had a secret affair with a young production assistant he met on the show, Willoughby took two weeks absence.
On her return she told viewers she felt "shaken, troubled, let down and worried for the wellbeing of people on all sides of what’s been going on."
She added: "You, me and all of us at This Morning gave love and support to someone who was not telling the truth.
"Who acted in a way that they themselves felt they had to resign from TV and step down from a career that they loved. That is a lot to process. And it's equally hard to see the toll that it'd take on their own mental health."
There had been reports of a behind-the-scenes feud between Willoughby and Schofield ever since 2022's Queuegate controversy.
The presenters came under fired over accusations they "jumped the queue" at the late Queen's lying in state at London's Westminster Hall in September.
Walker previously said that he hoped the "relentless hounding" of Schofield in the wake of the scandal would come to come to an end.
He tweeted: "I really hope the issues at This Morning are investigated and resolved.
“I hope that the individuals involved get the help they need and the show stays on air.
“I also hope the relentless hounding from some elements of the media stops.”
“People are clearly on the edge."
Watch: Dan Walker 'storms' off Good Morning Britain in dig at Piers Morgan