Actress and her DJ pal spend the day together

Lindsay Lohan celebrated her 22nd birthday yesterday by throwing an extravagant party with rumoured girlfriend Samantha Ronson.

The actress kicked off the day by going out to lunch with Sam at La Scala restaurant in LA before hosting a prom-themed bash at the Hollywood Roosevelt Hotel.

She changed into a pink chiffon mini-dress while Sam, 30, wore a tuxedo.

The pair decorated the room with pink, silver and blue balloons and Linds was treated to a pink birthday cake featuring a picture of Marilyn Monroe.

Lindsay’s mum Dina and younger sister Ali joined Sam, and Good Charlotte rockers Joel and Benji Madden, both 29, and The Hills actress Audrina Patridge at the star-studded bash.

SEE PICS: Lindsay Lohan celebrates birthday with Samantha Ronson>>

 

Alison Adey