Twain, 45, stepped out with Thiebaud, 40, for a PDA-packed lunch at Serafina's Fabulous Grill in NYC on Thursday with an enormous engagement ring.
"I've never seen Shania so happy," a pal tells Us of the singer. Swiss-born Thiebaud, a Nestle business executive, popped the question about two months ago in Switzerland.
The couple's road to matrimony was an exceptionally complicated one. Thiebaud is the ex-husband of Twain's former best friend Marie-Anne Thiebaud -- the woman Robert "Mutt" Lange, Twain's husband of 14 years, abruptly left her for in May 2008. (Both Lange and Marie-Anne denied the affair.)
Twain and Frederic reached out to one another in the wake of the stunning double betrayal, and were spotted vacationing together in Canada,Read More »from Exclusive: Shania Twain Is Engaged!