Fortuna quit the BBC ballroom show earlier this month after discovering that producers planned to put him in a dance troupe rather than pair him up with a celebrity.
Darren Bennett, Lilia Kopylova, Ian Waite and Matthew Cutler have also been dropped from Strictly's main lineup of stars but will feature in the new dance group.
Speaking to the Daily Star Sunday about the surprise shake-up, Bastian commented: "I absolutely respect Brian's decision - and I'll be really interested to see how the show goes.
"To be honest, it's such a great show and it's got such a charm that I think it will continue to go from strength to strength."
Bastian met Fortuna when they teamed up for the last series of Strictly. They confirmed their romance earlier this year.