Sandra Bullock ''has never been happier'' after reportedly adopting another child.

The 51-year-old actress, who adopted son Louis, now five, in New Orleans, Louisiana in 2010, is said to have fallen head-over-heels in love with her newborn daughter, but ''hasn't been getting a lot of sleep.''

A source close to the 'Gravity' star, who has yet to confirm rumours she recently became a mother for the second time, said: ''[The baby] has been fussier that Louis was at that age, and Sandy hasn't been getting a lot of sleep. The little baby has been very colicky, which has been stressful for Sandy. But even though Sandy has been sleep-deprived, she has never been happier!''

The Oscar winner's photographer boyfriend Bryan Randall, 49, who recently moved into her Los Angeles home, ''has been absolutely amazing helping Sandy with late night feedings, and keeping Louis occupied.''

The insider also told gossip website RadarOnline.com: ''Sandy is just overwhelmed with love for her two children, and her new relationship with Bryan.

''Sandra made it quite clear to Bryan from the start that she's looking for a husband to raise kids with. She had the paperwork ready to adopt another child but really wanted to do it with the right man, and Bryan's been checking every box so far.''

The brunette beauty originally planned to raise Louis with ex-husband Jesse James, but proceeded with his adoption alone following their split five years ago.

The source added: ''Everyone knows how terrified she is of giving her heart away again, but Bryan's incredibly supportive, loving and a brilliant father figure. Sandra says he's perfect.''