Britney Spears with Sean Preston in her armsThe “Britney Spears is pregnant” rumour mill has kicked into gear again. Access Hollywood and US Weekly are both reporting that the star is already five months pregnant - meaning baby number two would make its debut appearance in August, less than a year after Britney gave birth to her first child Sean Preston.

As well as being spotted with a “baby bump” while wearing a bikini, she was recently spotted shopping for baby clothes at baby boutique Petit Tresor in Los Angeles.

She’s also not helped speculation this time around by scheduling a mysterious press conference for this Thursday. She has handpicked journalists and media representatives, along with record industry executives, to attend the event in the Los Angeles Convention Center - but apparently not even her closest aides know what she will talk about.

Sony spokesperson Karen Phillips said: “Britney hasn’t held a press conference in so long that we know it’s something big - pregnancy, a split, we’re not sure.”

Her management team at the William Morris Agency are apparently in the dark too and are finding the star to be rather hard to deal with at the moment.

A source from the agency told TMZ.com: “she’s constantly changing her mind. One minute she wants to be an actress, the next minute she wants to fly to Maui to record a new album.”

“It seems like she’s not sure she knows what she wants to do, which makes being her agent frustrating.”