Credit: Josiah True/

Age ain't nothin' but a number.

So says singer/actress Sophie Monk, 31, who announced her engagement to 50-year-old American businessman Jimmy Esebag on Tuesday.

"I got engaged and I kept it quiet, so no one's heard much about him," Monk revealed during an Australian radio interview (via Sydney Morning Herald). "It feels right -- I think you know when you know."

Describing Esebag as her "soul partner," the Spring Breakdown star added that she's "marrying a male version of myself, which is dangerous but good. He's a keeper."

Before meeting Esebag, the native Brit dated Ryan Seacrest, Good Charlotte's Benji Madden and Entourage's Kevin Connolly.