But department store Debenhams has lost its spot in the broader FTSE 250, alongside online electrical retailer, AO World.
Debenhams is in the process of implementing an investment programme which involves closing some of its stores and warehouses temporarily.
The changes to the indexes will take effect on 19 June.
Property company, Segro will also join the FTSE 100, while Hikma Pharmaceuticals and Intu Properties will be demoted.
Joining the FTSE 250 are thread manufacturer Coats Group and turnaround specialists Melrose Industries.
On Wednesday Melrose announced a Â£144m bonus package to be shared between four of its top executives and further bonuses for a wider group of senior managers.
Also moving into the FTSE 250 are: IT services company FDM Group; hedge fund Pershing Square Holdings; fertiliser company Sirius Minerals; and the Georgian TBC Bank Group.
Leaving the FTSE 250 along with Debenhams and AO World are: the intellectual property group, Allied Minds; investment specialist, BH Macro; engineering business Keller; and private equity firm SVG Capital.
The make up of the FTSE 100 and 250 indexes is reviewed on a quarterly basis.
As the market value of companies change, they can drop in or out of the indexes which are adjusted four times a year.
In the latest reshuffle of the FTSE share market indexes, security company G4S is rejoining the FTSE 100.