Demi Lovato would marry Wilmer Valderrama now.

Wilmer Valderrama and Demi Lovato

Wilmer Valderrama and Demi Lovato

Professing her love for him, the 'Skyscraper' hitmaker has revealed she's ready to marry her 'That '70s Show' actor boyfriend, who she's been dating for four and a half years.

Demi said: "I am very, very in love with him. I think - we will probably wait a little bit longer (to get married), but - if he asked tomorrow I would say yes."

The 22-year-old singer went on to confess her parents were cynical about her relationship with the 35-year-old actor when they first started dating, due to the 12-year age gap.

Speaking to New Zealand radio station ZM, Demi said: "Whenever we were first starting to date about like five years ago, because I was 18 and he was 30, people were definitely judgmental and even like my parents were kind of like, 'I don't know why someone his age is wanting to date someone so young?'

"After a while, everyone started to see that what we have is real and incredible and very special and we have been together ever since."

At the weekend, Demi - who has opened up about her body anxieties and eating disorders in the past - gushed on Instagram about how Wilmer taught her to love her curves.

Captioning a photograph of herself posing in a skimpy outfit, she wrote: "Learn to lurrrrrvveee yerrrrr currrrrvveees I actually used to hate them...

"But then a special someone helped me learn how to love them... And he sure loves them.... #squats #COOLFORTHESUMMER (sic)"