If ever there was an athlete who could win the celebrity endorsement for love, it’s Washington Mystics forward Elena Delle Donne.

The former “Chicago Skyscraper” came out three years ago. Delle Donne is happily married to Amanda Clifton, and the couple was named The Knot’s first same-sex “Dream Couple.”

When we saw their wedding photos, we couldn’t get over the size of that wedding cake! Appropriately super tall, given that one of the brides is 6’5”.

Delle Donne and Clifton were graced by a bevy of bridesmaids, none more meaningful than Delle Donne’s big sister, Lizzie, seen here holding her “little” sister’s hand.

Holding hands, along with hugging, and a peck on the cheek, are among the only ways Delle Donne and her sister have ever been able to communicate. Lizzie is blind, deaf, autistic and has cerebral palsy.

“Lizzie doesn’t know that I play basketball,” Delle Donne told correspondent Andrea Kremer of HBO’s Real Sports with Bryant Gumbel. “She doesn’t know that I’m 6’5”. She just knows that I am one of her people, and a really important person in her life. And that’s all I want to be.”

Watch a preview of Kremer’s report below, and scroll down to read more about the Delle Donne sisters.

Their relationship is not what you might think, in terms of caregiver and receiver, Delle Donne said.

“I think people sometimes get it wrong. I’m not taking care of her. She’s taking care of me.”

In the exclusive report titled, “Love & Basketball,” Delle Donne spoke with Kremer about being gay, being tall, and her relationship with her elder sister, and how it’s always been what grounds her. Throughout her life and many challenges, Delle Donne has consistently chosen the path that kept her close to Lizzie.

And when she strayed from that path, it was never long before she course corrected, back to Lizzie.

The five time all-star has chosen to spend every off-season in Delaware with her Lizzie and her family, instead of playing overseas, where she could earn a seven-figure salary.

“Basketball was going to take me away from home, and I didn’t love basketball as much as I loved my family.”

The report on HBO, produced by Beret Remak, details her brief UConn Huskies career, all 48 hours of it, how she led the University of Delaware to a Sweet 16 appearance, why she left the Chicago Sky after four years, and how she knew Clifton was the woman she wanted to marry. All because of Lizzie.

Amanda Clifton (left), Lizzie and Elena Delle Donne

Watch “Love & Basketball” on HBO’s Real Sports with Bryant Gumbel throughout the month of May, or stream the episode online by clicking here (a subscription is required).

If you’d like to find out more about Elena and Lizzie Delle Donne’s relationship, check out “Lizzie,” the moving profile written by the basketball superstar about her sister for The Players’ Tribune in 2015.