A man in his 30s has been arrested on suspicion of causing grievous bodily harm during the incident in the Wentworth Mews area at approximately 1.20am.
The victims, one in his 30s and the other in his 40s, were taken to hospital and discharged after treatment, the Metropolitan Police said.
The force said the incident is being treated as a homophobic hate crime “due to insults shouted by the suspects”.
The London Gay Men’s Chorus described the assault as a “terrible attack”, which it said reinforces the importance of fighting back against homophobia.
The group is participating in Saturday’s Pride event in London, which is this year marking the 50th anniversary of the UK’s first Pride parade.
Chorus chairperson Peter Ptashko said: “This terrible attack only serves to underline how important it remains to fight against homophobia and all forms of discrimination.
“After 30 years, our mission of ‘social justice through song’ has never been more important to achieve a more equal, diverse and inclusive society that we all need today more than ever.”
Police said it is believed that more than one person was present.
Police have appealed to any witnesses who are yet to speak with officers to contact them.