The Good Morning Britain host revealed she and children Darcey, 13, and Billy, 11, were able to visit Derek for the first time over the festive period.
And she added that she is now terrified the new lockdown will hinder his progress as he is now longer allowed any visits even from Kate alone.
“How was Christmas in the end? We were all very concerned,” asked Kate’s co-host, Ben Shephard.
Kate replied: “It was tough, it was tough for everybody, I knew it would be tough.
“There was lovely moment, we did, over the period, get to see Derek and the children did for the first time, that was amazing.
“It was very heightened with emotion, because he is very changed.
“It was so wonderful, but it amplified how sad everything was and how different it is.
“But it was still fantastic and I am grateful to have had that opportunity and then instantly, now I am in a position where even I can’t visit.
“We are into lockdown, no visits at all, which I hope doesn’t continue for the whole of lockdown.
“Because that would be very impactful on Derek’s state.”
Derek has been in hospital since March 2020 after getting coronavirus, and it has wreaked havoc on his body, leaving him with diabetes and holes in his lungs and heart.
* Good Morning Britain airs weekdays on ITV at 6am