Isabelle's followers shared their congratulations in the comments, and there were even some sweet messages from her Gogglebox co-stars including Matty and Sarah-Marie as well as the Delpechitra family.
"DUDE I'M LOSING IT SO F***ING HAPPY FOR YOU," Bachelor in Paradise's Alisha Aitken-Radburn commented.
Married At First Sight's Sarah Jane Roza penned: "Congratulations!!! What beautiful news!!! Thrilled for you both xx"
Meanwhile Survivor winner and Looking For Alibrandi actress Pia Miranda wrote: "Ohhh congratulations!! So happy for you both."
Since Melbourne has gone back into lockdown, Isabelle and Alex shared the news with Isabelle's mum Kerry and grandmother Emme via video chat.
In two sweet videos that Isabelle posted to her personal account (watch in the player above), the bride-to-be revealed that her ring is one that Alex's mum gave to him when he was 18.
"Just about to go to bed and go to sleep and now you've knocked me out with one of these fantastic moments," Emme remarked before telling the newly engaged couple how happy she is.
"You've got a beautiful granddaughter," Alex can be heard saying in the background.
"I know, I fell in love with her the moment she was born, the very very moment she was born I fell in love with her," Emme sweetly replied.
Alex then says: "She deserves the best and I'll give her the best."
Isabelle split from her husband of five years Craig Silbery, who is also the father of her son, in 2017, however after five dates with Alex, COVID-19 happened.
"Alex and I realised we had two options: we could either pause things and take it online, or take a more MAFS approach, dive head-first and quarantine together!" Isabelle joked in a piece for Kidspot.
"We weighed it up, talked to friends and family and then decided to take the plunge. He packed a bag, two rolls of toilet paper (I was running out!) along with a bath towel, laptop and some wine, and set out on what has proven to be an interesting experiment: bunkering down at mine!"