Winfrey and Graham have been together since 1986, but largely keep their relationship out of the spotlight.
The couple were engaged in 1992 but never wed, and Winfrey later told Access Hollywood she doesn't believe she'll ever marry.
Oprah Winfrey and partner Stedman Graham cozied up for a rare photo on Valentine's Day.
The 62-year-old media mogul and 64-year-old businessman were all smiles in a snapshot Winfrey shared on Instagram captioned, "Stepping out with my Valentine of almost 30 yrs!
The couple were married in a spiritual ceremony on March 28 by Unity in Chicago minister Heidi Alfrey.
Wendy was born shortly after her parents, Stedman and Glenda were married in 1974.
PHOTOS: Oprah's hair evolution The media mogul, 60, took to Instagram on Thursday, Aug.
Daily Mail Online has learned exclusively that Stedman Graham's only child, daughter Wendy Graham, married an engineer named Bradley Kerwin Greene in March - and the couple had a beautiful baby girl named May.
Oprah and Stedman are over the moon that Wendy, 40, has found happiness with the 27-year-old Trinidadian.
I heard she said 'yes,' and Stedman couldn't believe it. " To Winfrey's surprise, some of her friends believed the report, so she set the record straight Sunday.
"6 people who know me well have called today congratulating me or surprised they weren't invited to my wedding," she wrote on Twitter. "Winfrey and Graham became an item in 1986, and a few years into the relationship, the businessman proposed.