Singer/actress Demi Lovato has brushed off fresh speculation she is set to wed boyfriend Wilmer Valderrama after receiving a new ring for Valentine's Day (14Feb16).

The Skyscraper star took to social media app Snapchat on the most romantic day of the year to show off her new sparkler with a photograph of her holding Wilmer's hand.

"So in love..." she captioned the image.

Despite wearing the piece of jewelry on the middle finger of her right hand, some fans became convinced the unusual rock was an engagement ring, and began sending the 23-year-old their congratulations.

However, Demi moved quickly to silence the claims as she shared the same snap on Instagram.

"You are my world, my life, my best friend, my love and my purpose," she wrote in the sweet caption. "I love you so much Wilmer... y'all are crazy btw (by the way)... That is my RIGHT hand and my MIDDLE finger I am NOT engaged."

She later declared her love for her man once again by posting an image of the pair as they enjoyed their romantic evening.

"I love this man with ALL of my heart," she gushed. "#HappyValentinesDay".

Demi's latest engagement denial comes days after the star told talk show host Ellen DeGeneres she is not heading down the aisle just yet - not that she would mind if her man proposed.

"I don't see a ring (but) I wouldn't mind if I saw one," she laughed on The Ellen DeGeneres Show, which aired in the last Wednesday (10Feb16).

Demi, 23, and Wilmer, 36, have been dating "on and off" for five years, and the singer added, "There's time for everything."