Demi Lovato: Happy Birthday, Simon Cowell!

Demi Lovato stops off at a gas station to fill up her new convertible with a gal pal on Sunday afternoon (October 7) in Beverly Hills, Calif.

The two stopped off at a salon and the 20-year-old singer came out with a bag of Unite products.

PHOTOS: Check out the latest pics of Demi Lovato

“Today is a great day…,” Demi wrote on Twitter, “it’s @SimonCowell’s birthday which means he’s even OLDER now!!! #HappyBirthdaySimon.”

Stay tuned to JJJ for a first look at Demi‘s Teen Vogue cover!

10+ pics inside of Demi Lovato…