Takei said he asked Altman to help him train for a marathon, they fell in love, and now they've been living together for 21 years.
Altman said he proposed by getting down on one knee in their kitchen while Takei was eating a sandwich after seeing on TV that the California Supreme Court had legalized same-sex marriage. It surprised Takei, who thought he would be the one who popped the question.
They bought each other turquoise and silver wedding rings. Takei and Altman plan to marry Sept. 14 in the Democracy Forum at the Japanese National Museum in Los Angeles.
Walter Koenig, who played Chekov in "Star Trek," will be the best man and Nichelle Nichols, who played Uhura, will be the matron of honor. Castmate Leonard Nimoy will be among the 200 guests, but probably not William Shatner. Takei has said Shatner didn't treat him and most of the cast very well.
Takei, who had a recurring role on NBC's "Heroes" last year, and Altman plan to honeymoon for a month in South America. As for what they'll wear on their big day, Altman said they'll both walk down the aisle in white tuxedoes, which seemed to catch Takei off-guard.
"Well, now that you've announced it on the air, I guess it's settled," he said.
