Dustin Lance Black, the Oscar winning screenwriter who is currently dating Daley, will be named as a witness in a lawsuit against the X-Men filmmaker.
The allegation comes from aspiring actor Michael Egan, who claims Singer promised him a part in a film but drugged and raped him in LA and Hawaii when he was still a teenager.
Dustin is being called as a character witness for Egan, but he is also a close friend of Bryan Singer, who he looked upto in the industry.
The 39-year-old recently relocated to London in order to spend more time with boyfriend Daley, and despite the pair being avid social media users they enjoy the privacy of their relationship - something which may be disrupted if Dustin is questioned during the trial.
Olympic diver Tom announced he was gay via his YouTube channel in December, when he also revealed that he was happily in a relationship with a man.
Michael Egan's lawyer confirmed that he plans to call Dustin to arrange for him to stand as a witness, saying: 'I intend to take depositions of all individuals who may have relevant information, including Singer's friends.'
Dustin has attended parties at the X-Men director's house previously, and was known to both the defendant and the alleged victim.
It has not been suggested that Dustin was present when the alleged attacks took place.