The Modern Family actress and the businessman – who got back together last month after splitting up in May following a series of arguments – have got engaged as the brunette beauty celebrates her 40 birthday in Mexico, a source has confirmed to Us Weekly.

An insider said: "They have a crazy relationship. They break up and make up. They fight and make up hard!"

Vergara – who turned 40 yesterday - has been celebrating the milestone at a Mexican resort over the past few days alongside 90 loved ones, and she has was spotted wearing a diamond ring on her left ring finger on Monday, Wonderwall reported.

The brunette star previously married Joe Gonzalez - with whom she has a son, Manolo, 20 – in 1991 but the pair divorced in 1993.

Vergara and Loeb have been dating for more than two years after meeting at a Golden Globes party in 2010, and following their split last month she is said to have moved into a hotel, but friends admitted at the time that they were unsure the separation would be permanent.