The glamour model was snapped wearing a £25,000 diamond band on her ring finger while standing on the balcony of the couple's home in Essex.
Sources say that Falcone proposed during filming in Marbella for upcoming TOWIE special The Only Way Is Marbs, which airs on Wednesday, June 13.
According to The Sun, Falcone popped the question while taking a cruise with Mecklenburgh in scenes that producers have been trying to keep secret until broadcast.
The couple previously split during the third series of TOWIE when Mecklenburgh cheated with ex-boyfriend Mark Wright, but they later reunited.
Both admitted last year that they were "still trying to establish trust" after the affair and their relationship was jeopardised again when Falcone was discovered to have sent flirtatious messages to a number of girls.
The Only Way Is Marbs airs June 13 at 10pm on ITV2.