The 'Home Alone' star is reportedly eager to tie the knot with his US soap star girlfriend Jordan Lane Price before his pregnant ex-girlfriend marries Ashton Kutcher to prove he is finally over the 'Black Swan' star.
A source told the National Enquirer: "Macaulay is convinced that Jordan's the one for him. They are crazy about each other."
Jordan has been touring with the former child star's cover band The Pizza Underground in recent months.
The source added: "The band may be a joke, but Macaulay's love for Jordan most definitely is not. They could be formally engaged within weeks, and married by summer. Mila has her eye on a summer wedding as well, so it will be interesting to see who gets to the altar first."
Mila, 29, split from Macaulay, 33, in 2011 after eight years together and the brunette beauty was single until she started dating her former 'That 70's Show' co-star Ashton, 36, in April 2012.
The actress is reportedly thinking about tying the knot with her fiancé in a registry office in Los Angeles as soon as possible so she can focus on her pregnancy, but she previously insisted being married wasn't important to her.
She said: "Not to say that I don't believe in it, but it's just not something that's important to me.
"But I will have children. I'm too selfish to have them now, but when I do, I don't feel like I need to be married."