"Take it Grell." Ke$ha tossed a handful of glitter at the reaper with enthusiasm.
Grell stood up on the roof of a building and gave London a clear view of his fabulousness.
"Don't want your money. I've got my own."
Ke$ha joined in from in top of a chimney.
"And your not my daddy. Baby I'm full grown."
The two continued to sing in unison.
"Don't complicate it. Don't tell me lies. I'm not your girlfriend and I ain't never gonna be your wife."
Suddenly a whirring filled the air and a blue police box materialized.
"Damn it Ke$ha. Get back to your own time period." The grey haired Scottish man inside shouted.
A pair of hedge clippers shot through the air and hit Grell right in the eye. "Please stop messing around, Grell. You have work to do." William retracted his scythe, dragging the Crimson reaper along with it.
"Why do you torture me so?" Grell sighed dramatically.
On the roof, The Doctor chased Ke$ha down and pulled her into the TARDIS. "Now you stay there while I collect Jack." He commanded.
"Fiiiine." Ke$ha groaned.
"Jack sounds hot. Let's wait for him." Grell struggled against William's grip.
William sighed as he tugged a struggling Grell off into the darkness of an alleyway and off to the reaper realm.

Told ya.