11/25/2013 11:22 EST | Updated 11/26/2013 08:07 EST

Nathan Fillion American Music Awards 2013: 'Castle' Star Rocks Red Carpet In Smart Suit (PHOTOS)

When is Nathan Fillionnot adorable?

The "Castle" star attended the 2013 American Music Awards on Sunday and looked like he had the second best time of his life (the first being when he filmed "Firefly," obviously).

Wearing his usual charming grim on the red carpet, the 42-year-old rocked a smart black suit but was missing one important accessory: Girlfriend Mikaela Hoover!

Update: Fillion was joined by a mystery brunette, who some fans are saying is Spanish actress Christina Ochoa. Guess he wasn't dateless after all!

The actor probably had more fun than Miley Cyrus, Katy Perry and Justin Timberlake combined.

From presenting with his "Miss Match" co-star Alicia Silverstone to photobombing Lady Gaga to hanging out with actor Jeremy Renner, the handsome star looked as if he didn't want to leave!

Fillion shared his enthusiasm for the show with his Twitter followers, noting that AMAs host Pitbull was excellent at his duties and that singer Ariana Grande's performance was astounding.

We love ya, Nathan!

Don't Nathan and Alicia make a cute pair?

Photo gallery Nathan Fillion See Gallery