The 25-year-old faces Argentina’s Yamila Abellaneda for the WBA Intercontinental title at the Nottingham Arena on Saturday.
Former WBC and IBO super featherweight champion Harper had been due to face Heather Hardy only for the American to suffer a wrist injury in the build-up to the fight.
Top 15 lightweight and WBA world-ranked Abellaneda, 28, comes into the contest at short notice with a record of 13-4-1.
Harper lost her world titles in dramatic fashion when she was knocked out on her feet by the USA’s Alycia Baumgardner at the Utilita Arena in Sheffield last November.
“I’ve worked so hard over the last months and I can’t wait to show you all my improvements,” she said on Twitter.
The fight is on the Wood-Conlan undercard and live on DAZN.