Gearing up for another round of performances, Britney Spears arrived in Australia on Wednesday morning (November 4) - landing in Sydney before transferring out to Perth.

Of the trip, the "Gimme More" singer tweeted, "Longest flight ever but we had a great time ... So excited to be here."

As previously reported by Gossip Center, Miss Spears will be performing 15 concerts in Australia, starting in Perth on Friday.

From there, it's off to Melbourne, Sydney and Brisbane before wrapping up her Circus duties in Adelaide on November 29th.

Prior to flying into LAX Airport this morning, Rihanna was busy breaking in the stage on a brand new cruise liner in Ft Lauderdale, Florida on Thursday night (November 19).

Looking fabulous in a bright yellow ensemble, the Barbadian beauty performed at the first ever concert on Royal Caribbean's Oasis of the Seas cruise ship.

Meanwhile, Rihanna recently chatted with Atlanta's Q100 about rumors of a budding romance with Tristan Wilds - which she shot down.

"This is funny: I had a house party, and you know how you hold house parties and people come over you don't even know," she says. "He came by, brought his friends, and everyone was hanging out, but I don't even have his number. So I don't know how I could be dating him."

She's always up for a swanky event outing, and last night (November 19) Michelle Trachtenberg was spotted at the 2009 Victoria's Secret Fashion Show.

The "17 Again" hottie looked amazing as she arrived at the Big Apple shindig, sporting a sexy strapless textured black dress with matching clutch and silver heels.

In related news, Michelle has announced that she's following the celebrity designing trend and releasing a line of jewelry with Coach's youth-oriented Poppy Line.

When describing the new line, Trachtenberg explained it has a very "Marie Antoinette meets Blondie" vibe, with a mixture of romance and edginess.

Continuing work on her latest project, Cameron Diaz was spotted having a blast on the set of "Knight and Day" in Salzburg, Austria yesterday (November 19).

The "Charlie's Angels" hottie looked to be in good spirits as she joked with the cast and crew in between scenes at Festspielhaus, also taking a few moments to wave to fans who were watching nearby.

Up to this point, Cameron has been filming in Boston, Massachusetts and the Salzburg shoot is expected to last for about a week. Earlier this month, hundreds of local Austrians tried out for roles as extras.

Miss Diaz stars alongside Tom Cruise in the new action comedy flick, under the direction of James Mangold. "Knight and Day" is scheduled for a Summer 2010 release.