Adele Roberts is running the London Marathon in aid of charity Heads Together, which is supported by Prince William and Catherine.
"Huge thanks to people like Adele," Prince William told hosts Scott Mills and Chris Stark.
The prince also revealed he had previously texted in to Radio 1, under an assumed name.
Along with song requests, he's also asked for - and got - a shout out from former Radio 1 DJ Sara Cox.
Speaking about their mental health campaign, Prince William described how "eye-opening" the experience had been.