10/01/2013 02:50 EDT | Updated 10/03/2013 02:04 EDT

Nathan Fillion Gets Cozy With 'Castle' Co-Star Susan Sullivan At TV Event (PHOTOS)

Mikaela Hoover better be ok with boyfriend Nathan Fillion getting close with his co-stars!

The former "Firefly" actor was photographed acting really chummy with his "Castle" co-star Susan Sullivan while posing at a media presentation of "The Wait Is Over! 'Castle' Is Back!" in Beverly Hills on Monday. Wearing his trademark monochrome suit, the actor hugged and kissed Sullivan who looked pretty in a matching black-and-beige ensemble.

But not to worry Mikaela, the 42-year-old Edmonton, Alta.-born actor wasn't pulling a move on the 70-year-old actress! Sullivan plays Fillion's mother on the show so it's no wonder that the two are very affectionate with each other.

In fact, at a press event earlier in September, the actress sang her handsome co-star's praises, saying:

"Who wouldn't want Nathan Fillion in their life? He is the most delightful man you can imagine." Awww, we're melting in our seats!

Luckily for Nathan's girlfriend, she gets him all to herself! The 29-year-old actress has been dating the Twitter fan since 2010 and made quite the impression when she walked the Emmys 2013 red carpet with her beau.

Call us jealous!

Love ya, Nathan:

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