Donny & Marie unveil headlining variety show at Flamingo Las Vegas. (PRNewsFoto/Flamingo Las Vegas, Ethan Miller/Getty Images)

That was fast.

Donny Osmond's doctor-mandated absence from singing will be over tonight, after a week's rest for "vocal fatigue," reports Las Vegas Sun columnist John Katsilometes.

Donny will rejoin his sister/singing partner, Marie, tonight for their headlining show at The Flamingo in Las Vegas.

Donny missed a week of performances, and Marie sang either alone or with a substitute partner.