The actress and TV personality announced the happy news on her U.S. daytime talk show The View on Wednesday, revealing that the pop star had proposed with a yellow sapphire.
Showing off her new ring, the former model told her guest hosts, "I just got engaged!" and then burst into tears as Wahlberg joined her on the set.
The couple started dating last year after Wahlberg appeared as a guest on McCarthy's short-lived late-night TV show.
Both stars have been married once before and McCarthy, 41, insisted she would never wed again after breaking up with boyfriend Jim Carrey in 2010. But she admitted she was warming to the idea of life with Wahlberg, 44, in a TV interview at the end of 2013, stating, "I've said on every interview that I was like, 'Never get married again, ever', and, of course, you never say never. I think he would be an amazing husband, so if he does (propose), I would for sure say yes."
Cooing about her new fiance on The View on Wednesday, McCarthy added, "He understands my work schedule and he has his and I get it. And we're both single parents and he's trying to juggle all of that while I am too."
Wahlberg has two sons from his nine-year marriage to Kim Fey, which ended in divorce in 2008, and McCarthy shares a son, Evan, with her ex John Asher. They divorced in 2005.