Hett's "Coronation Street"-themed coffin was taken to Stockport Town Hall in Greater Manchester by horse-drawn carriage Friday for his funeral".
Crowds spilled out of the building and gathered on the street outside to celebrate his life as they watched the service on big screens.
BBC Radio One DJ Nick Grimshaw recorded a video message which was played, calling Mr Hett a "true inspiration" while comedian Jason Manford also sent a video tribute saying "the world has been robbed of a potential superstar".
The dress code was "black and fabulous" and the mood bittersweet as Martyn Hett, an icon for the millennial generation, went out "like a diva" today.
In the post he also praised Michelle McManus for her lovely singing at the funeral.
In the message, she said: "I just wanted to say that I love you and I'm so happy that we got a chance to meet and I know you're shining down on us from heaven".
The PR worker became friendly with the Scottish singer, helping promote her gigs on social media and even made a 24-hour bus journey to see her in concert.
"I mentioned the Waterside Arts Centre to Martyn and he was just so excited and assured me that he'd sell the whole evening out for me with just his mates alone".
"I will never forget Martyn and he will always be in my thoughts", she added.
"Martyn actually had discussed and planned his funeral and the way he wanted to exit", she said.
Mrs Murray said: "It seems that he was fearless about life as well because he wasn't frightened of talking about his own death".
Thousands are expected to attend, as Martyn's stepfather Stuart Murray said he had the "ability to make people feel special".
Mr Murray said: "I think he's just a sad, misled person".
A small private service was held for friends and family after the public memorial ended.
A funeral service is also due to be held today for 15-year-old victim Megan Hurley, from Halewood, Merseyside.
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