The mum-of-one announced the happy news with as post on her Instagram account, sharing an image of her dazzling ring with a cartoon couple pasted over the top.
'I said yes!!!' she exclaimed in the caption.
In response to the sweet snap, a spokesperson for Evan, 26, confirmed the news, and told the Daily Mail that 'they are extremely happy'.
Miranda and Evan met in 2014 and made their relationship public in June 2015. At the time, Miranda explained that the couple 'were really good friends for a long time before we started dating'.
The Victoria's Secret Angel has been married once before, to actor Orlando Bloom, and the pair have a son, Flynn, 5, together. In October 2013, Miranda and Orlando revealed that they had separated several months earlier, and eventually filed for divorce.
Miranda with her son Flynn, from her marriage to actor Orlando Bloom
When she began dating Evan, Miranda said she waited around six months before introducing the social media mogul to her son.
'My ex and I decided] that we had to know the person for six months and feel good about them [before introducing them to Flynn],' she said.
'Evan met Flynn, so yeah, things are going well. Orlando thinks he's great. We're just a modern family now!'
Miranda and Evan pictured together in 2015
In previous interviews, Miranda has said that she fell for Evan because he is 'sweet, really kind and smart'.
Explaining that the pair favour a similar relaxed lifestyle, she added, 'He's 25 but he acts like he's 50.'
'He’s not out partying. He goes to work in Venice [Beach], he comes home. We don’t go out. We’d rather be at home and have dinner, go to bed early.'