Celeste is the ex-wife of former Ohio governor Richard Celeste. She lives in Lakewood, Ohio.
Eight bishops from Roman Catholic Womenpriests-USA (RCWP) will take part in Keldermans' ordination, including her predecessor, Bishop Joan Houk of South Bend, Indiana, who retired in December 2018.
Keldermans, 64, was elected by the 24 women priests of the nine-state Great Waters Region in October 2019, and her bishop's ordination was set for April 25, 2020 before the pandemic halted it.
Keldermans recently said she was "humbled" Mayr-Lumetzberger of Austria and Celeste were attending.
"It means that our movement is continuing, that there is a whole web of support," Keldermans added. "It's also life-giving, that we're here to stay."