JD Gyms has applied to take over an empty unit at Birchley Island Retail Park in Oldbury, which has been built on the site of a former Toys R Us store.
In the application to planners, the gym's agent says: "JD Gyms is taking occupation of the vacant unit and intends to commence its operations shortly."
Sandwell Council has approved the application, which includes the installation of a mezzanine floor without the need for planning permission.
Birchley Island Retail Park, off Wolverhampton Road and near the M5, opened earlier this year in place of the Toys R Us store that closed down in 2018 before standing empty for two years.
Discount retailer B&M was the first store to open in May when it welcomed its first customers to its shop and garden centre.
A few days later, Canadian coffee shop chain Tim Hortons opened its new restaurant and drive-thru at the site.
JD Gyms will occupy a currently vacant unit next to B&M.