Los Angeles: Pop diva Britney Spears who is set to launch her 'Femme Fatale' summer tour has shed 20 pounds after banning alcohol and junk food from her diet.

According to a reliable source, the 29-year-old singer has shed the pounds due to her strict diet regime. "Britney's dropped 20 pounds since her heaviest," said a friend.

The 'Toxic' singer, who has banned booze, sugar and white flour from her diet, has been working out with her boyfriend Jason Trawick.

"The best thing she ever did was cut out alcohol. It was bloating her, upsetting her blood sugar and causing her cravings," added the friend.

The source admitted that the pop star has indulged in pizza, cookie-dough ice cream and greasy tacos for a long time, adding to her body and mind problems.

The source also added, “It stressed her out and added to her weight gain. It was a vicious cycle. Now, she seems to finally have control."