Photo: Derek Hough/ Twitter

"Vampire Diaries" actress Nina Dobrev celebrated her 24th birthday on Wednesday, Jan. 9, and fans couldn't help but wonder what her on-and-off screen boyfriend, Ian Somerhalder, was going to do (or get) for the celebration!

On Wednesday Somerhalder tweeted at his girlfriend:

"You Jules are correct! Happy Birthday beautiful @ninadobrev! RT @juliePlec Am I wrong or is it the gorgeous @ninadobrev's birthday?!!!"

While the message was sweet, "Vampire Diaries" fans were shocked when Dobrev didn't spend her birthday with Somerhalder at the People's Choice Awards. Somerhalder was on hand with "Happy Endings" actress Casey Wilson to present the award for favorite comedic actor ... but Dobrev was nowhere in sight.

Ian Somerhalder Photo: Reuters

So, where was the Bulgarian beauty? At the Dior dinner! The 24-year-old hung out with fellow vampire Nikki Reed ("Twilight's" Rosalie) and Anna Kendrick before long time boyfriend Ian Somerhalder arrived.

The pair displayed some cute PDA while on hand at the event, and even snapped a shot with "Dancing With The Stars" pro Derek Hough! The photo of Somerhalder and Dobrev with Hough has since made its rounds online and not just because it's a cute photo ... but because some are speculating that the "Vampire Diaries" co-stars are engaged!

In the photo, Dobrev has a wide smile across her face as she wraps her right hand around her boyfriend and holds a glass of champagne in her left hand. But it's actually another photo of Dobrev that has the engagement rumors swirling. PerezHilton.com got their hands on a photo of the actress in her car at the Dior dinner, and when zoomed in, fans can see a sparkly gold ring on her left hand. While Perez Hilton immediately jumped to the conclusion that Ian Somerhalder finally popped the question, Dobrev's rep told GossipCop.com that any engagement reports are "totally untrue."

Do you think Nina Dobrev and Ian Somerhalder are engaged? Sound off in the comments section below!

Are you a Nina Dobrev and Ian Somerhalder fan? Also check out:

Nina Dobrev And Ian Somerhalder Dating; 'Vampire Diaries' Heartthrob Wishes Dobrev A Happy Birthday On Twitter

'Vampire Diaries' Stars Ian Somerhalder And Nina Dobrev Spending The Holidays Together

'Vampire Diaries' Star Ian Somerhalder Donates Personal Copy Of '50 Shades Of Grey' For Charity