Jean Claude Manseau, 25, known as Jo, and Jake Heaton, 19, were on the tram on 1 November when they say a man started shouting homophobic abuse.
The pair had been singing songs from the musical Wicked. After leaving the tram around 1am they went towards Canal Street, famed for its gay bars.
At that point they say a group of around 15 men attacked them.
Jean-Claude told the Manchester Evening News it has "destroyed every bit of confidence I have."
He said it would be a while before he felt safe enough to go back into the city centre.
He added: "They split my forehead, my lip, broke my nose. My eyes are black and swollen. My ribs are painful, I can't move much."
Now the Manchester Gay and Lesbian Chorus have planned a Safe to Sing event to help bolster the confidence of LGBT (Lesbian, Gay, Bisexual and Transgender) people in the city.
They plan to sing songs from Wicked on Monday 17 November, and will be joined by Manchester's Halle choir.
The choir posted on Facebook: "It's difficult to express the impact of this attack on the LGBT community because so many of us have fought so long to make Manchester a safe place for people like Jo and Jake."
The group will be singing on the Metro at 8pm on Monday and will post song sheets on their website so everyone can join in.
They've even created a poster in green Wicked colours.
Rachel Fox, a member of the choir, told BBC Newsbeat: "This is about the LGBT community getting together and saying we won't stand for this. We want to reclaim the areas in which the men were attacked, on the metro and in Piccadilly gardens.
"We want to reach out to the LGBT community to encourage them to come out, join us and be proud. Our straight allies are absolutely welcome. If you love someone, if you have a family member or friend in the LGBT community then you are part of this community as well.  Hopefully this will be a mass sing off."
Manchester Lesbian and Gay Chorus Musical Director Loz Kaye said: "As it says in the lyrics of the musical Wicked 'you can't pull me down'. Nobody is going to pull us down."
Police are investigating the original attack and are looking for a white man in his early 20s with short hair, and a group of black or mixed race men.
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A gay and lesbian choir will stage a musical takeover of the Manchester Metrolink after two young gay men were attacked.