Less than a week after tweeting a portion of the lyrics to her new song 'Who Says,' actress-singer Selena Gomez has revealed the entire track -- a catchy song with a message about believing in yourself.

Gomez unveiled the track this morning on Ryan Seacrest's radio show. The bouncy pop song opens with the 18-year-old singing, "I wouldn't wanna be anybody else," a line she repeats several times throughout the song.

"I'm no beauty queen / I'm just beautiful me," Gomez continues, sending the message that real beauty is on the inside.

The song's hook asks a series of rhetorical questions meant to inspire self-confidence:

"Who says you're not perfect? / Who says you're not worth it? / Who says you're the only one that's hurting? / Trust me, that's the price of beauty / Who says you're not pretty? / Who says you're not beautiful?"

Gomez goes on to suggest that anybody can be president, star in movies or be the best at whatever they do if they just believe it and don't allow anyone to convince them otherwise.

'Who Says' is expected to appear on the next Selena Gomez & the Scene record, which hits stores later this summer. Chris Applebaum directed the 'Who Says' music video, set to premiere on the Disney Channel on Friday.

We'll see if the song's infectious tune and positive message allow Gomez to join her boyfriend Justin Bieber in the Top 10.

Listen to Selena Gomez, 'Who Says'