AceShowbiz -

Despite previous denial, speculations that Nina Dobrev and Derek Hough are in a relationship just simply refuse to die down. Although both stars' representatives have not confirmed nor denied the romance, according to sources close to the pair, they started seeing each other in August and are now already "somewhat serious" in their relationship.

Prior to being linked to Hough, Dobrev was dating her "The Vampire Diaries" co-star Ian Somerhalder. The 24-year-old actress and the 28-year-old choreographer, connected by way of dancer Julianne Hough, being her BFF and his sister, exchanged tweets after Derek won his first Emmy on Sunday, September 22.

"@Derekhough !!!!!!!! #EMMYWINNER I cant express in 140 characters how unbelievably excited+incredibly proud I am of you. You deserve this," Dobrev wrote on her Instagram, captioning a photo of Hough holding his Emmy trophy. She followed it up with a photo of the Hough siblings with the words, "I wish I wasnt filming so I could have been there to celebrate w/u guys!"

Not being able to contain her excitement and adoration for Derek, Dobrev sent out this beautifully-penned, eloquent note, "@derekhough Those of us touched by your light got to watch you brighten up the rest of the world. Keep shining!" To all these sweet messages, Hough replied with a simple tweet, "You're the best babe."