EastEnders and Carry On legend Barbara, 83, is suffering from Alzheimer's disease, having been diagnosed with the devastating condition in 2014.
In recent months, Babs' dementia has accelerated to the point that her husband Scott Mitchell was forced to move her into a care home in mid-July.
Concerned, presenters Kate Garraway and Charlotte Hawkins asked after Babs' health on the show, as the interview with the actor drew to a close.
Giving viewers an update, Ross said: "The reason I'm doing this today is because I'm effectively standing in for her."
He continued: "I spoke to her on FaceTime on Sunday with her husband Scott.
"She recognised me but I think we all have to be realistic that there is no cure for Alzheimer's presently and it's probably not going to get better for her."
Urging viewers to leave a red poppy in their windows in support of Remembrance Day, he added: "It's an honour to be talking on her behalf."
Charlotte replied: "She's very much in our hearts at the moment."
Making a plea for viewers to support The Royal British Legion, despite the reduction in collections this year, he explained: "There’s normally around 40,000 people out on our streets collecting for the Royal British Legion.
"We know that’s going to be down by some 30% at least, so this year every poppy counts."
He added: "I know there are a lot of people out there suffering. We know that particular in the armed forces community there are people suffering."
From the early 90s onwards, Ross played Babs' onscreen son on EastEnders, rising to fame as barmaid Peggy's son Grant Mitchell.
Since their respective EastEnders exits, Ross and Babs have remained close, though he hasn't been able to visit her in person during the lockdown.
In June, Ross revealed Babs was struggling to recognise herself, as he told GMB: "The nature of the disease is that initially she knew who I was and then in three minutes turned to me and asked who I was.
"She looks at pictures of herself - from her incredible career - and she asks ‘who’s that lady?’"
Good Morning Britain airs on weekdays at 6am on ITV.