The TV presenter – who announced at the weekend he had developed mild symptoms and so would be self isolating until further notice – said he was entitled to a test as a government-designated "essential worker".
Morgan, 55, tweeted on Monday evening: “My COVID-19 test was negative. I was advised to take the test by my doctor after developing possible coronavirus symptoms, and was entitled to do so as a Govt-designated essential worker. I'll be back on @GMB as soon as my doctor advises I'm OK to return to work.”
The presenter said he will seek medical advice before returning to the Good Morning Britain sofa.
Ben Shephard, 45, is currently standing in for Morgan on the ITV breakfast show, which he co-hosts with Susanna Reid, 49.
Morgan tweeted on Sunday evening: “On medical advice, and out of an abundance of caution for a mild symptom that arose in past 48hrs, I’ve had a test for COVID-19 and so won’t be working on @GMB until I get the result back, which should be tomorrow.”
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Discussing his absence from the show on Monday, Dr Hilary Jones to said: "I spoke to Piers yesterday he doesn't have symptoms that are normally associated.
“It doesn't affect us here in the studio because we're practising strict social distancing.
Shephard joked: "Did he just want a lie-in? Is that it Hilary?"
Reid added: "I think he just wanted to get his car cleaned."
The TV presenter lives with his wife, journalist Celia Walden, 44, and eight-year-old daughter Elise. He previously revealed his youngest son Albert, 19 – who he does not live with – had displayed symptoms of coronavirus.
Morgan’s co-presenter Reid was absent from the ITV show for two weeks herself while she self-isolated at the beginning of lockdown after her son showed mild symptoms of coronavirus.
She has three sons – Finn, Jack and Sam – with ex-partner Dominic Cotton, from whom she separated in 2014.
During her quarantine period, Reid appeared on GMB several times via video link. Morgan is yet to do so.
Morgan falls into the essential worker category as Good Morning Britain is deemed a “public service broadcast”.
However, Morgan’s long-term ‘frenemy’ Lord Sugar branded him a “hypocrite” for accepting a test for coronavirus when they are still on limited supply.
Lord Sugar tweeted: “@piersmorgan not an Govn-designated essential worker. There're [sic] Nurses, Doctors, Police, Army,train and truck drivers. He deprived a real essential workers from a test.If this was Hugh Grant, Meghan or other of his enemies like me. He would be howling from the rooftops. HYPOCRITE.”