Gay rights activist Rory O'Neill has urged Repeal the 8th campaigners to be tolerant, warning that the upcoming abortion referendum "will not be gay marriage part two".
O'Neill, whose stage name is Panti Bliss, said those who want the legislation changed must include everyone in a cool-headed "national conversation" about abortion.
The star, who was polled in TIME magazine as one of the most influential people in the world, said campaigners should steer clear of "metropolitan elitism" that can isolate large sections of society.
"It's very easy for passion to become anger, but that puts people off," he said. "There is a time and a place for righteous anger - and I am not saying everyone should be meek - but you need to think strategically when it comes to referendums.
"Sometimes you might want to stand up and scream your head off, but not when you are trying to speak to the middle ground.
"When it comes to abortion, it's sometimes forgotten that you can give someone all the facts as you see them but you won't change a mind that believes abortion is murder. They are not misogynists or monsters for [believing] that."
Equally, he cautioned, it is pointless for campaigners to just agree with each other in the safety of a bubble. He said the referendum would hinge on the middle ground whose minds were open to change.
"Those two sides (pro and anti) will never reach a consensus," he said. "What I would like to see in the public sphere is a grey-area view. That view should be given a platform to work out the issues.
"The vast majority are somewhere in between and we need to make a concerted effort to hear those middle-ground voices."
And he warned those who voted Yes to gay marriage not to assume the favour will be returned by the LGBT community - because "even a gay communist" can be against terminations.
O'Neill (48), who is from Ballinrobe, Co Mayo, said: "You can be a gay communist and still believe life begins at conception."
There was a further meeting of the Citizens' Assembly yesterday to discuss the Eighth Amendment.
Ireland's Catholic bishops and the Pro Life Campaign criticised the use of the phrase "fatal foetal abnormality" in the assembly's agenda, with the bishops' spokesman stating the terminology depersonalised the foetus and sought to "normalise abortion".
The pro-life lobby stated the term "life-limiting conditions" should be used instead.
Chair Ms Justice Mary Laffoy opened the assembly, telling the 99 volunteers: "The correct use of terminology in this debate is an issue which has been causing both myself and the secretariat some difficulty in settling our minds to.
"It is a contentious aspect to the arguments around the topic we are discussing. It is argued, for example, that the term 'fatal foetal abnormalities' desensitises what is a very difficult and traumatic diagnosis for a woman and her baby.
"Many medical practitioners tell us that this is a term that they do not use when speaking to a woman about a diagnosis," she added.
"Nonetheless, the term is widely used and is very much in common parlance - to exclude its usage at the Assembly would therefore, in my view, be inappropriate. It will therefore be used and will continue to be used."
Later, the assembly heard that Irish hospitals were "struggling" with a shortage of counsellors to deal with women who have had abortions and suffered psychological issues afterwards.
Dr Peter McParland, of the National Maternity Hospital, in Dublin, said maternity hospitals did not have enough counsellors and needed more.