Rihanna donned a platinum wig and some cat-eye sunnies for an impromptu photo shoot with her bestie, photographer Melissa Forde.

The singer Tweeted "Just another day at the office" with these sexy snaps.

It's not the first time Ri's gotten her Marilyn on ... in the single "Love Without Tragedy/Mother Mary" on her latest album Unapologetic, the 25-year-old sings: "Red lipstick, rose petals, heartbreak / I was his Marilyn Monroe. Brown eyes, tuxedo, fast cars / A James Dean on the low."

Hmmm ... wonder who her James Dean is ...