Shenae Grimes and Matt Lanter, <I>90210</i> Shenae Grimes and Matt Lanter, 90210

When last we saw Liam and Annie, they shared a tender moment on Liam's hand-built boat before creepy Jasper blew it to smithereens.

Ah, but a little explosion can't stop love on 90210, Matt Lanter tells

Check out photos of the 90210 cast

Liam (Lanter) has confessed to the coins, Annie (Shenae Grimes

) has confessed to the crash, and now there's nothing to stop things from heating up between them — and soon. (90210 returns Monday, Sept. 13 at 8/7c on the CW.)"We'll get romantic in the first couple of episodes. We share a kiss," Lanter teased during a break from filming a rather hot scene — not involving Annie — from a future episode. (Peek at a paparazzi pic from that day.) But things won't stay easy for long. "It gets complicated very fast. There will be a love triangle involving Liam, Annie and Liam's half-brother Charlie (guest star Evan Ross)," Lanter says.

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"Charlie and Liam are estranged," the actor explains. "His half-brother hasn't been in his life so they don't have a good relationship. Throw a girl into the mix and it's that much worse."What does Charlie have that Liam doesn't? Lanter says Charlie's older, more educated and — look out, Liam! — into theater. "Annie's into that," he says. "They have that connection. They can read plays and Shakespeare together, and that's something Liam doesn't have — something more worldly, cultured, maybe."

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Lanter is rooting for Liam and Annie to make it long term. They're a couple that the actor says he saw coming since Season 1."There's always been some chemistry between Annie and Liam," he says. "In the first season finale, he was really flirting with her. Picking on her, yes, but in a flirting way. She was this good girl, but also had this façade on — Liam was determined to break that down.  He was always curious about the real Annie. And I think that's where it started. Now the've bonded over really personal things, so there's an even deeper emotional connection."

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Wait, no love lost for Naomi (AnnaLynne McCord)? Lanter says the two girls are different. "Liam's relationship with Naomi started out as a physical one and it stayed that way.  From what we saw, they never really formed an emotional attachment. But with Liam and Annie, we've seen it grow. It grew out of friendship."Having said that, Lanter says, it's hard to choose a favorite. "I got one foot in both camps, man," he says, laughing.Do you think Liam and Annie will make a good couple?