T-Boz tears up on Capitol Hill. (Andrew Lightman for the National Marrow Donor Program)

Venue: Rayburn House Office Building

Cause: African-American Bone Marrow Awareness Month

Bona fides: Lead vocalist for ’90s mega-girl group TLC; chronic sickle-cell and arthritis sufferer (though not currently in need of a transplant).

Backup: Del. Donna Christensen (D-V.I.), Dr. Jeffrey Chell of the marrow donor program.

What she wants: To help more African-American blood-disease patients find transplant matches by recruiting more blacks to join the national bone-marrow registry, where minorities are underrepresented.

How she looked: Unabashedly glamorous. No Hollywood-goes-to-the-Hill pantsuit, for once. Flowing black-and-white maxidress, shiny black-and-gold platform sandals, black wrap, chandelier earrings, blonde bob baring pale tattoo on the back of her neck.

How she sounded: Earnest and emotional, recalling childhood days in the hospital. “Y’all know, I’m also fighting for myself as well,” she said, and started to cry. “I want to grow old and live to see my grandchildren.”

Final plea for donors: “I’m African-American and Native American and Irish. We’re genetically whatever. So we need to help each other out.”