Brothers & Sisters, Gilles Marini Brothers & Sisters, Gilles Marini

It's Valentine's Day on Sunday's Brothers & Sisters (OK, a week late) and Sarah Walker will find herself with more than one suitor as her former French flame, Luc Laurent, returns to throw a wrench into her love life.

"We meet again! And it's like everything she tried to fight before is staring at her right in the face," Gilles Marini, who plays Luc, tells "Even though she's with Roy [Jay Karnes], she falls [for Luc] again because she's still madly, madly in love with him."

Gilles Marini returning for more Brothers & Sisters

The last time viewers saw Luc, he was packing his bags for France after he and Sarah (Rachel Griffiths

) came to blows about his carefree lifestyle and apparent lack of career direction. But in an attempt to win her back — he did text her three weeks ago — the painter has secured himself a job."He's working. He's showing her that he's serious and is here to win her back because Luc believes with all his heart that they're meant for each other," Marini says. "The story between Sarah and Luc is very simple: It's an old-fashioned love story. There's nothing under it except pure love for each other. That's what I like and I think that's why audiences like it. It's very clear and our hearts are very pure for each other. Lately on TV, I've been seeing a lot of unfortunate love stories, so I like that we're portraying something pure and beautiful."

Brothers & Sisters: Gilles Marini's French lover "could be it" for Sarah

The only thing that is not simple is how their rekindled relationship will move forward. Although the whole Walker clan has embraced Luc, conflicts will emerge with certain family members as Luc gets "deeply involved" with the Walkers, Marini says. Chief among their concerns: Exactly who is the guy underneath the hunky exterior?By the third episode he's in, the actor says, "you will understand much more of who he is, why he is the way he is today and why he has so much love for Sarah. Luc Laurent did not have the childhood that normal people have. It's very twisted. He grew up with things that he maybe shouldn't have seen. It's made him the man he is today. There's a beautiful moment between the two of them because they understand they come from different backgrounds and try to deal with it. You find out pretty much everything about him, or at least enough to understand who he is."The Dancing with the Stars alum insists there is still no agenda with Luc, despite him not having shared these secrets with Sarah before. That was only because he didn't know what he had until he lost it, Marini says.So now that Luc is back, is he here to stay? Marini will appear in all of the remaining episodes of the season except for the April 11 flashback episode. And after that, there is a "huge chance" he will return as a regular next season, Marini says.

Brothers & Sisters casts young Walkers for flashback episode

"I think they're waiting to see how the new arc is doing. There are a lot more ups and downs coming up — a lot of stuff he has to settle back home. Remember — he's not American," he teases. "And obviously the show needs to be officially picked up too, but I'm just concentrating on the day-to-day and doing the best job I can. This is a dream job. To work with all these people? Wow! The writers continue to surprise me with what they come up with, and these new episodes are amazing. You'll definitely see much more of Luc this time."Not to mention much more skin."A lot more clothes come off," says Marini, who memorably bared all in the Sex and the City movie. "Michael Morris, one of the directors and producers, shot one of the scenes of us ... and he told us it was so beautiful. It's intimate and sweet — and we show a lot. I know it will be the talk in the offices the next morning."