"They were on his balcony, then went back into his room and the lights went out."

The couple were seen leaving the hotel at 2am clutching a bottle of champagne before taking a late-night drive in Criss' Rolls Royce.

The amorous pair then returned to the hotel, having reportedly ordered Britney's bodyguard to pick up condoms.

Criss, who has recently been romantically linked to Cameron Diaz, is currently involved in messy divorce proceedings with his wife Joanne Sarantakos.