The 39-year-old will be appearing on the BBC medical drama for three episodes, portraying the part of brassy Barbara Alcock.
Barbara is a mature medical student and single mother. Full of positivity, curiosity and enthusiasm, Barbara is delighted to be learning from established regular Elliot Hope (Paul Bradley).
A Holby City statement teased: "Over-eager to begin with, Barbara soon blossoms under Elliot's tuition. But when she suffers a setback academically, will he be able to give her the confidence she needs to pursue her dream of becoming a doctor?"
Osho makes her first appearance on Holby on Tuesday, June 19.
Her previous acting credits include roles in Paradox, Psychoville and EastEnders.
Watch Andi Osho's 2011 appearance on Let's Dance for Comic Relief in the video below: