The couple have only been dating since July and have not yet confirmed their engagement publicly, but a source told E! that Manganiello popped the question on Christmas Day.
Vergara was previously engaged to Nick Loeb. Vergara and Loeb called off their two-year engagement in May 2014, citing work commitments and time spent apart as reasons for their split.
The Year of Gore: Check out 2014's grossest (and most stomach-churning) TV moments!