Although Demi Lovato hasn't spoken much about her romance with Wilmer Valderrama, she tweeted adorable photos of them together along with a special birthday message to the actor.

"To the funniest, most inspiring, incredible man I know..@WilmerValderrama - thank you for helping me get through my darkest moments.. You truly are a light to this world and to my life.. Happy Birthday!!!" she wrote on Twitter.

In the three photos posted, a pink haired Lovato posed with the former That '70s Show actor and the pair also made goofy faces in two.

The actor, who turned 34 on Jan. 30, responded: "Who needs presents when the gift of you is real to us all.. Thank you for the blessing of knowing you."

The couple's romance reportedly started back in 2010, around the same time Lovato entered rehab. Two years later, Valderrama spoke highly of the younger star during a candid interview with Perez Hilton.

"We were really just best friends and to be honest I couldn't be more proud of her. She's a great human being," he said in 2012. "But I was very proud to be there for her when she needed me and she was there for me a number of times too... She's definitely someone very special to me."

Recent rumors even emerged that the couple is engaged after Lovato posted a photo of herself on Jan. 29 on Instagram with a ring on that special finger. However, a rep for the star told E! News that there is "no truth to reports claiming she and Wilmer are engaged."

Tags: Demi Lovato wilmer valderrama