Britney Spears celebrated Halloween with her sons Sean Preston and Jayden James as well as her boyfriend Jason Trawick and her mom Lynn Spears in London last night. Britney twittered a picture of her sons' costumes, which were Batman for Jayden and a ninja for Sean Preston. Britney was decked out in one of her Femme Fatale costumes and Lynn was a witch, while Jason skipped putting on any dress-up gear. Britney is currently in the midst of the European leg of her tour and Joe Jonas is her opening act for these overseas dates. Britney gave Joe Jonas a lap dance during the interactive part of the show which has previously had her wrapped around Pauly D from Jersey Shore as well as her real-life love Jason. Mr. Trawick also recently starred in Britney's very sexy "Criminal" music video, though it looks like this year the two skipped any couples costumes for their Halloween festivities.