Kelly said: "He will be missed. He was that Marmite factor, you either loved him or you hated him. But he will be missed.
"And do you know what, he was a very loyal friend as well. You have to take your hat off to him and wish him well."
Singh replaced Morgan as Reid's co-anchor this morning after Morgan stepped down from the ITV breakfast show on Tuesday evening.
Singh was quick to point out that she was not his official replacement, saying: "I was here anyways, don't read anything into this, I was here anyways this morning.
"I've shifted seats on this brand-new desk and I am glad to be here to sort of go through the programme with you today. It's a strange morning for all of us here."
She added: "From our point of view Piers is a unique individual and he ruffled feathers. Whether you loved him or hated him, he shaped our industry.
"He is a big character and lots of people have got in touch to say, you know, 'This was always on the cards', people are glad that he's gone, many viewers will be absolutely gutted this morning.
"People want to know what he thinks, and people like to hear whether they agree with him or not."
Watch: Susanna Reid says the show must go on after Piers Morgan has left GMB
Reid acknowledged that the dynamic between her and Morgan, who had been her co-anchor on the show since 2015, had been a big part of GMB, but insisted that the show must go on.
She said: "It has been a rollercoaster ride. We've had our ups and downs and you know, as viewers, we have had our disagreements – that is the dynamic of the programme. But he has made the decision to leave and so it is looking very different."
Reid added: "There are many voices on GMB and everyone has their say. But now Piers has decided to leave the programme. Some of you may cheer, and others will boo.
"He has been my presenting partner, Monday to Wednesday, for more than five years, and during Brexit and the pandemic and other issues, he has been a voice for many of you, and a voice that many of you have railed against.
"It is certainly going to be very different. But shows go on. And so, on we go."
Morgan, 55, left GMB after Ofcom launched an investigation into remarks he made on Monday about Meghan Markle that sparked more than 41,000 complaints.
In an interview that first aired in the US on Sunday night, the Duchess of Sussex said she had approached people in the royal “institution” for help after she had suicidal thoughts, but was turned down.
Morgan said on Monday's show: “Who did you go to? What did they say to you? I’m sorry, I don’t believe a word she said, Meghan Markle.
"I wouldn’t believe it if she read me a weather report."
ITV announced Morgan's departure on Tuesday evening, saying: "Following discussions with ITV, Piers Morgan has decided now is the time to leave Good Morning Britain.
"ITV has accepted this decision and has nothing further to add."
Beresford said: "I understand that you've got a personal relationship with Meghan Markle, or had one, and she cut you off. She's entitled to cut you off. Has she said anything about you since she cut you off? I don't think she has. But yet you continue to trash her."
Morgan got up from his seat at the GMB desk and began to walk out saying: "OK, I'm done with this. Sorry. See you later. Can't do this."
Watch: Piers Morgan joining GB News?