Sunday night, what are you doing to us?!

Not only is it the Golden Globes, but it's the season premiere of HBO's Girls, as well as Showtime's stellar lineup of Shameless, Episodes, and House of Lies. And to celebrate its talented stars and preview Sunday night, Showtime threw a swanky soiree at West Hollywood hot spot Cecconi's, sponsored by Samsung.

Emmy Rossum, gorgeous in a gray leather J. Mendel sheath dress and a vintage Ralph Lauren clutch, explained that Fiona is a bit of a mess at the start of season five. "She just got out of jail and is kind of attracted to her Narcotics Anonymous sponsor/boss, played by Dermot Mulroney. He's not a bad guy to be attracted to, but not when he's your NA sponsor!"

Don't expect Fiona to put all her eggs in one basket with Mulroney's character though. "She's also kind of flirting with these two guys who are customers at a restaurant," Rossum reveals. "Meanwhile, there's a mysterious woman flirting with her who we don't know yet is in cahoots with Jimmy/Steve. He'll be back, so there's a lot in store for her. There's a lot of men and love interests, but I think it's more about her trying to define herself through them, and eventually she's going to have to take a look at herself instead of trying to find herself through them."

But let's rewind to Dermot Mulroney's casting for a moment. A self-confessed fan of My Best Friend's Wedding, Rossum told me that she was thrilled when he came on board. "I kept teasing Dermot when I met him by singing the theme song to the movie. Every time I'd walk in the room!" So how did Mulroney react? "He blushes! Did you know he's a concert cellist too? He gets hired to play on movie scores all the time. He's like a legit musician, so I don't think he takes me too seriously. I think he's so dreamy and an amazing actor."

So amazing in fact that Rossum gives Mulroney the praise usually reserved for the show's lead, William H. Macy. "He's not afraid to really go for it in a way that really reminds me of Macy. He's really fun and fits in really well with our crew."

It's a sentiment that Rossum's costar Shanola Hampton echoes as well. "I've learned how close a cast can be and how much like a true family it is when you get the right group of people [together]."

Speaking of Hampton, what's in store for Veronica this season? Well, now that Kevin and Veronica have kids, they "aren't the Kevin and Veronica we once knew," Hampton reveals. "It will be a different way that the audience will experience these two characters, and I'm not sure they are going to be very happy with Veronica a lot of the times."

Shameless returns Sunday night to Showtime at 9 P.M. ET/PT.

What do you want to see happen in season five?