Jonathan Lilley, who has been dating partner Tom Jenkins for two years, got down on one knee in front of his friends and family who were dressed as their favourite Star Trek characters.
After visiting the bridge set at London’s ExCel centre, Mr Lilley produced a ring while all of his friends gathered around the couple to hear Mr Jenkins reply “yes”.
Mr Lilley said he had been planning the romantic proposal for three months.
It is believed to be the first ever same sex proposal to take place at a Star Trek convention.
His partner Mr Jenkins said: “I am over the moon and completely shocked. I love John so much for what he has done and I am so thrilled and honoured we have made history today.”
However this wasn’t the only proposal, as fans waited for the TNG cast reunion hosted by William Shatner, a fan named Gary proposed to his his longtime boyfriend, Eamonn. Eamonn accepted, the two men hugged and the crowd exploded in applause.