Caitlyn revealed to the Daily Star: “I talked to her the other day and as soon as we got on the phone, that voice of hers, I was like, ‘Oh my God, that voice of hers, it has a familiarity.'”
While Derek was first taken into hospital six months ago with COVID-19 and is unable to speak, doctors have warned he may stay in his current condition.
Last month Kate confirmed her partner regained minimal consciousness but is still in intensive care.
The presenter and her children, Darcey, 14, and Billy, 11, who she shares with Derek, only recently had the chance to see him for the first time since he went into hospital.