Demi Lovato has thanked her friends and family for ''supporting [her] happiness'' after she announced her engagement.

The 27-year-old pop star's beau, 29-year-old actor Max Ehrich, popped the question this week, and the couple have been inundated with messages of congratulations from the likes of Paris Hilton, Noah Cyrus, Jessie J and Meghan Trainor after they shared the news on social media.

Socialite Paris commented under Demi's Instagram post - which included a series of snaps of the couple on an engagement photo shoot - with: Congratulations gorgeous! I'm so happy for you!''

Noah wrote: ''so happy for youuuu i love u so much (sic).''

Jessie gushed: ''SO HAPPY FOR YOUUUU. (sic)''

And Meghan added: ''Congratulations!!!!!! so happy for you!!!!!!!! (sic)''

Demi - who first started dating Max in March - added: ''To all of my friends and fans commenting - I F******LOVE YOU - THANK YOU FOR SUPPORTING MY HAPPINESS (sic)''

In the announcement, Demi gushed that she's ''honoured to accept'' Max's hand in marriage.

The 'Tell Me You Love Me' hitmaker admitted she has ''never felt so unconditionally loved by someone in my life'' since her parents and declared she is ''officially going to be someone else's partner''.

Demi also hinted that she and her now-fiance are keen to ''start a family''.

She wrote on Instagram: ''When I was a little girl, my birth dad always called me his 'little partner' - something that might've sounded strange without his southern cowboy like accent.

''To me it made perfect sense. And today that word makes perfect sense again but today I'm officially going to be someone else's partner.''

She added: ''@maxehrich - I knew I loved you the moment I met you.

''It was something I can't describe to anyone who hasn't experienced it firsthand but luckily you did too.. I've never felt so unconditionally loved by someone in my life (other than my parents) flaws and all. You never pressure me to be anything other than myself. And you make me want to be the best version of myself. I'm honored to accept your hand in marriage. I love you more than a caption could express but I'm ecstatic to start a family and life with you. I love you forever my baby. My partner. Here's to our future!!!! (sic)

In his own post, Max gushed about how Demi is his everything and admitted ''words cannot express how infinitely in love with you I am forever and always''.

He wrote: ''Ahhhh. You are every love song, every film, every lyric, every poem, everything I could ever dream of and then some in a partner in life. Words cannot express how infinitely in love with you I am forever and always and then some. I cannot spend another second of my time here on Earth without the miracle of having you as my wife. here's to forever baby ahhhhhhhhhhhhhhhhhhh jeuejfjqjweuvu I'm so excited you are the most beautiful inside and out in the entire world & I couldn't be more grateful God brought us together I LOVE YOU SO MUCH @ddlovato AND WILL FOREVER CHERISH YOUR PURE, BEAUTIFUL, INFINITE SOUL (sic)''