The 'Just Give Me A Reason' hitmaker already has two-year-old daughter Willow with husband Carey Hart, reported Ace Showbiz.
The 34-year-old star tweeted, "I love that every time I find a box of Girl Scout cookies I'm pregnant. Guilty: I'm having a thin mint."
The singer's mysterious comments come shortly after her husband was spotted rubbing her stomach in New York City last month.
Pink, whose real name is Alecia Hart, said last year she is desperate to extend her family because she thinks motherhood is the best thing.
The couple got married a year later in Costa Rica on January 7, 2006.