Play video content EXCLUSIVE TMZ.com

Caitlyn Jenner should be stepping up her game repping the transgender community in the U.S. before she jets to the U.K. to address Parliament ... according to "RuPaul's Drag Race" star Carmen Carrera.

There's been backlash over the diversity speech Caitlyn is supposed to give Wednesday because some people in the LGBTQ community, including Carmen, don't think she's a great flag bearer. Facts are ... Cait's a white, rich, conservative woman who's also world famous.

Carmen's point is Caitlyn's gotta connect better with the common trans woman. Y'know ... put some thigh-high boots on the ground in the community.