"I love Piers Morgan and you haven't always got to agree – that's why free speech is important and I admire that, he stands by his front,” Sweeney said.
Morgan quit GMB in March after receiving a backlash for saying he "didn't believe a word" of Meghan Markle revelations in her interview with Oprah Winfrey. The Duchess of Sussex had revealed that she had felt suicidal after appealing to Buckingham Palace officials for support.
Explaining her stance, Sweeney continued: "He's got balls of steel and I'm a big fan of Piers, big fan, and I supported him publicly on social media and then didn't look at my Twitter for a week because I knew I would get absolutely abused but I didn't care."
The BBC Radio Merseyside presenter went on to say she thinks he is “sorely missed” on the ITV breakfast show because he “shook it up”, and that it's not the same without him.
Sweeney, 50, showcased her support for the former newspaper editor by sharing Morgan’s Mail On Sunday column in which he broke his silence on his departure to her 51,600 Twitter followers.
She quote tweeted the article saying: "Brilliant article @piersmorgan. Miss you so much on @GMB."
Morgan’s departure from the show last month came after he said he didn’t believe the Duchess of Sussex’s claims and “wouldn’t trust her to read a weather report”, in comments that attracted over 57,000 complaints to the broadcasting watchdog Ofcom.
Meghan's claims in the interview included that she had been denied help from Buckingham Palace officials to seek help for mental health issues and that there had been discussions prior to the birth of her son Archie about his potential skin colour.
The following day, Morgan walked off the GMB set after an on-air row with weather presenter Alex Beresford, who was there to discuss his experiences with racism.
Shortly afterwards, Morgan said he would not be returning to the programme.
Watch: Piers Morgan says Sussexes did 'hit job' on Royal Family