Elin Nordegren's tycoon boyfriend Chris Cline has earned his stripes with Tiger Woods' ex-wife ... in a BIG billionaire way.
The two jetted off for a ski trip to St. Moritz, Switzerland -- it's where the rich go to ski -- and looked real cozy on the mountain ... after arriving by helicopter!
36-year-old Elin met Chris, who's 21 years older, when she started building her post-divorce, mega-mansion in Palm Beach ... right next to his beachfront palace. They split in 2014, but got back together late last year.
You know what they say -- couples who ski together, do NOT golf together ... especially with their exes.