Star Trek actor George Takei has said the decision to make Sulu gay in the forthcoming film Star Trek Beyond is "really unfortunate".
The 79-year-old played the character as heterosexual for decades on screen, but the latest film sees Sulu, played by John Cho, married to a man.
The move had been intended as a tribute to Takei, who is openly gay himself.
But Takei said, while he welcomed a gay character, it was "a twisting" of creator Gene Roddenberry's vision.
Speaking to The Hollywood Reporter, the actor said Roddenberry was exhaustive in conceiving his Star Trek characters, and he had always envisioned Sulu as heterosexual - although he never had an onscreen love interest.
"I'm delighted that there's a gay character," said Takei, a strong supporter of LGBT rights.
"Unfortunately, it's a twisting of Gene's creation, to which he put in so much thought. I think it's really unfortunate."
He added that when he first learned last year, from Cho, that Sulu would be revealed as gay, he tried to convince the writers to create a new gay character instead.
"I told him, 'Be imaginative and create a character who has a history of being gay, rather than Sulu, who had been straight all this time, suddenly being revealed as being closeted'."
Pegg: 'I must respectfully disagree'
When Star Trek Beyond director Justin Lin later contacted Takei to confirm the decision, the actor again urged him against it.
Takei said he had been led to believe writer Simon Pegg - who had conceived the idea as an homage to the actor's legacy and LGBT activism - had changed his mind on the issue, until a month ago when he received an email from Cho asking for advice on what to say on the forthcoming press tour.
A disappointed Takei told the Hollywood Reporter he was "not going to change" his mind, adding: "I really tried to work with these people when at long last the issue of gay equality was going to be addressed.
"After that conversation with Justin... I interpreted that as my words having been heard."
However, in a statement released to The Guardian on Friday, Pegg took issue with Takei's point of view, saying he "must respectfully disagree with him".
"I have huge love and respect for George Takei, his heart, courage and humour are an inspiration," Pegg wrote.
"He's right, it is unfortunate - it's unfortunate that the screen version of the most inclusive, tolerant universe in science fiction hasn't featured an LGBT character until now.
"We could have introduced a new gay character, but he or she would have been primarily defined by their sexuality, seen as the 'gay character', rather than simply for who they are, and isn't that tokenism?
"Justin Lin, Doug Jung and I loved the idea of it being someone we already knew because the audience have a pre-existing opinion of that character as a human being, unaffected by any prejudice. Their sexual orientation is just one of many personal aspects, not the defining characteristic.
"Also, the audience would infer that there has been an LGBT presence in the Trek Universe from the beginning (at least in the Kelvin timeline), that a gay hero isn't something new or strange.
"It's also important to note that at no point do we suggest that our Sulu was ever closeted, why would he need to be? It's just hasn't come up before."
Star Trek broke new ground
Takei said he had once suggested to Roddenberry the issue of homosexuality was worth exploring on the sci-fi TV series back in 1968.
It came after the show had already broken new ground depicting one of the first interracial kisses to be broadcast in the US, between Captain Kirk and Lt Uhura.
"He was a strong supporter of LGBT equality, but he said he had been pushing the envelope and walking a very tight rope - and if he pushed too hard, the show would not be on the air," Takei said.
The actor, who came out as gay in 2005, said he had to keep his homosexuality a secret when he first made Star Trek in the 1960s in order to continue working in television.
He married his partner, Brad Altman, in 2008.