Demi Lovato told her mother she was ''gonna marry'' Max Ehrich within the ''first few days'' of their romance.

The 'Anyone' singer and 29-year-old Max got engaged after just four months of dating earlier this week, and now her mother, Dianna De La Garza, has revealed Demi always knew Max would be the man she'd marry because he's ''her person''.

Writing on both Twitter and Instagram, Dianna said: ''Welcome @maxehrich into our crazy, loving family... @ddlovato told me after the first few days with you, 'I'm gonna marry this one, Momma!' Becuz she knew she'd found her person. I couldn't be happier that you both found each other. You fit perfectly in our family. Congrats to both of you!! (sic)''

And the actor responded: ''Over the moon to be a part of it, Love you!!! (sic)''

In Demi's announcement, the 27-year-old singer 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)''