Robin Roberts, who has long shielded her romantic life from the public, came out on Facebook on Sunday.

The popular co-host from ABC's Good Morning America, who has been a key part of the show's ascent to No. 1 in the morning television wars, posted a picture of her dog, KJ, along with this message:

Flashback 12/29/12....Hard to believe this was 1 year ago today..when I reached a critical milestone of 100 days post transplant...and KJ was finally allowed to come back home.



Reading this comforts me and I hope the same for you: "If you are depressed, you are living in the past. If you are anxious, you are living in the future. If you are at peace, you are living in the present."



At this moment I am at peace and filled with joy and gratitude.



I am grateful to God, my doctors and nurses for my restored good health.



I am grateful for my sister, Sally-Ann, for being my donor and giving me the gift of life.



I am grateful for my entire family, my long time girlfriend, Amber, and friends as we prepare to celebrate a glorious new year together.



I am grateful for the many prayers and well wishes for my recovery. I return every one of them to you 100 fold.



On this last Sunday of 2013 I encourage you to reflect on what you are grateful for too.



Wishing you a Healthy and Happy New Year.



Peace, love, and blessings to all..XO

Though she had been shy about her dating life until now, Roberts has famously shared her health struggles with the public. She was diagnosed with breast cancer in 2007 and underwent treatment to cure it. In June 2012, at age 51, she announced that she had been diagnosed with myelodysplastic syndrome, a blood and bone marrow disease. She had contracted MDS, she said, from her treatments for breast cancer. Roberts' sister was a bone marrow match for her.

The month before, Roberts had scored a huge interview for ABC: President Obama announcing his reversal on same-sex marriage. Roberts' popularity and charm surely contributed to Obama's advisors choosing her for the interview. But was her sexuality, an open secret, also a factor? The media, which still do not know how to write about such questions, did not speculate.

Roberts now joins Jodie Foster, Wentworth Miller, Maria Bello, Jason Collins, and Tom Daley — among others — as a celebrity who has come out in 2013. As the evolution of LGBT rights continues to be a dominant political and cultural issue — from the wave of states that allow same-sex marriage to the Duck Dynasty disaster — the act of coming out has evolved. As with Daley and Bello, Roberts came out by mentioning her relationship with a partner of the same sex, rather than identifying herself as a lesbian or bisexual.

ABC News issued a statement of support: "We love Robin and Amber, who we have all known for a long time. We were so touched by Robin's Facebook message today and so thankful for all the loving support she has in her life."

The Amber of Roberts' post, by the way, appears to be Amber Laign; her Twitter avatar looks to be KJ the dog!