The pair were enjoying a night out at the LAX nightclub in the Egyptian-themed Luxor hotel on Saturday with Christina's husband Jordan Bratman.
But Paris shocked the married couple by grabbing the microphone and paying tribute to the Beautiful singer by telling the packed crowd: 'Congratulations to the most beautiful pregnant woman in the world - you're gorgeous.'
Christina's pregnancy has been a constant rumour for a number of months but has yet to be confirmed officially by the couple, so Paris' outburst may not have been totally welcome.
However, the 26-year-old was more successful in dealing with relationships during her time in prison, as she recently revealed she had won the support of her fellow inmates during her 23-day sentence for a drink-driving offence.
She said: 'They would say, "I love you, God bless you, it's ridiculous you're in here. I'm here for murder, what the hell is going on?"
'People thought the judge was totally out of order.'
