The 41-year-old 'Samantha Who' actress revealed the news of her engagement on a TV show and also flashed her ring, reported Ace Showbiz.
"He's lovely," she said, adding that they have already picked a wedding date and location, but refused to disclose the information.
Esposito divorced Cooper after only four months of marriage in 2007.
Meanwhile, Dowler previously dated Kate Winslet who is now married to Ned Rocknroll. Dowler was dumped by Winslet after she met Rocknroll while on a holiday with the model at a Caribbean hideaway that belongs to Richard Branson.