Harrison, who has kept a low-profile since making racially insensitive comments earlier this year, tagged Underwood in a post, writing, "Very proud of you today...Happy to see you stand up and openly live your truth. You have my love and support my friend."
In an emotional interview on Wednesday's Good Morning America, Underwood said he's the "happiest and healthiest I've ever been in my life."
"I've ran from myself for a long time. I've hated myself for a long time," the 29-year-old reality star told Robin Roberts. "And I'm gay. And I came to terms with that earlier this year and have been processing it. And the next step in all of this was sort of letting people know."
Celebrities like Andy Cohen, Meghan McCain and more expressed well wishes on social media.
Underwood, who starred on The Bachelor in 2019, received support from former Bachelor and Bachelorette stars, too. Demi Burnett, who competed on Underwood's season and later came out as bisexual on Bachelor in Paradise, tweeted, "Welcome to the community."
Nicole Lopez-Alvar, Tahzjuan Hawkins and Onyeka Ehie, who all appeared on Underwood's season, also weighed in.
While Underwood's openness is mostly being celebrated on social media, his relationship with winner, Cassie Randolph, has been put back in the spotlight. The couple split in spring 2020 after nearly two years together and the breakup was tumultuous.
Randolph was granted a temporary restraining order in September against Underwood after he allegedly stalked and harassed her and her family. In November, she asked the court to drop the order and the police investigation was reportedly also dropped at her request. In Underwood's sit-down on Wednesday, he apologized specifically to Randolph for "any pain and emotional stress" he caused.
"I wish that I would've been courageous enough to fix myself before I broke anybody else," he said, noting he "loved everything" about Randolph, which "only made it harder and more confusing" in terms of his sexuality.
"I got into a place for me in my personal life that was dark and bad. I can list a bunch of different things but they'd all be excuses," Underwood told Roberts. "But I think overall the reason why now is because I got to a place where I didn't think I was ever going to share this. I would have rather died than say, 'I'm gay.' And that was sort of my wakeup call."
Underwood is reportedly filming a reality series for Netflix that focuses on living his life publicly as a gay man, according to Variety.
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