Demi Lovato's fiancé feels like the ''luckiest man'' to be with the singer.

The 'Cool for the Summer' hitmaker's beau Max Ehrich heaped praise on the singer as he marked her 28th birthday on Thursday (20.08.20).

Taking to Instagram, he wrote: ''Words fall short baby. You light up this world & I am the luckiest man alive to call you my fiancé ... I keep falling more in love with you and your pure heart & soul every moment ... Can't wait to make endless memories with u & forever cherish you with all my heart. Happy 28th, my angel @ddlovato (sic)''

Meanwhile, Demi previously admitted she is ''falling more and more in love'' with Max ''every day''.

Posting pictures of the pair enjoying a sweet kiss, the 'Anyone' wrote: ''Falling more and more in love everyday with you honey (sic)''

Whilst Max responded in the comments: ''more and more every moment baby. thank you for all that you are. I am truly the luckiest man in the world. Cheers to forever and then some (sic)''

Max, 29, is also said to be hugely supportive of Demi's ongoing recovery following her near-fatal overdose two years ago.

The source explained: ''Max is supportive of her recovery. Her family and friends are happy for her.''

Whilst another insider said: ''Since Demi started seeing Max, it's been obvious she is loving life. He is a great guy, and it's amazing to see her this happy.''

In July, Demi announced she was engaged to Max.

She wrote: ''@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 honoured to accept your hand in marriage.''