Insiders claim the romance began after the pop star and actor appeared on MCCarthy's Vh1 talk show in March (13), when the racy pair discussed their sexual preferences.
MCCarthy blogged about her encounter with the singer, writing, "Being turned on by a guy is always fun but to have it legitimately happen to you on Tv is to be turned back into a 12-year-old."
Reports suggest the two stars have enjoyed a number of dates and even spent America's Independence Day (04Jul13) together.
Wahlberg's nine-year marriage to Kim Fey ended in divorce in 2008, while MCCarthy has dated Jim Carrey and American football star Brian Urlacher since the end of her marriage to John Asher in 2005.
Wahlberg has two kids from his marriage to Fey, while MCCarthy shares a son with her ex-husband Asher.