Former West Ham players including Matt Jarvis, James Collins and Anton Ferdinand, joined first-team coach Kevin Nolan plus a number of supporters from the club's LGBTQIA+ supporters' group Pride of Irons and Inclusive Irons at the bar's special launch event.
The Hammers Pride Bar offers a social space to encourage people to hold positive conversations about how we can all support the LGBTQ+ community and help create inclusive environments where everyone feels welcome.
"We never imagined when we started that we would be having events like today," said Lorna Severn from Pride of Irons. "We get people messaging us after these events saying 'I didn't know you existed and I'm so pleased.'
"There are going to be fans and players that, for various reasons, can't come out, can't be who they are, and I just think that what we can do - what we have done - is give visibility to people who can't be visible, give them a voice. You can't take away the importance of that."
The theme of this year's Rainbow Laces campaign is "Lace up, to Keep it Up", focusing on the progress made over the last decade, and the ongoing commitment to ensuring football is inclusive and welcoming to everyone.
This resonates greatly with former midfielder Jarvis, who made 205 Premier League appearances for the Hammers, Wolverhampton Wanderers and Norwich City.
"It's amazing to see what's been done, especially Pride of Irons, in the last 10 years," said Jarvis, now a West Ham ambassador.
"To make everyone feel inclusive and be able to go to the games, to support their teams and feel safe, I think that's the biggest message that everyone wants to hear - that you can go to games and support your team, feel safe and feel inclusive in the world of football."
The launch of Hammers Pride Bar comes less than two months after the Premier League recognised West Ham's ongoing dedication and commitment to equality, diversity and inclusion by presenting the club with the Advanced Level of the Premier League Equality Standard (PLEDIS).
Hammers Pride Bar is based in Hackney Wick. It will be open to all for the duration of the Rainbow Laces campaign, from 2-7 December, at "Two More Years", a bar close to West Ham's London Stadium home.