The shocking romance comes just week after the reality hunk broke off his engagement to show fiancé Vanessa Grimaldi.
According to a Page Six source, Jones and Viall got together after she told show host James Corden that she was a Bachelor super-fan.
"You don't know if you like him or if he's a scumbag, but that's why I'm attracted to him, maybe," January Jones said of now-boyfriend Nick Viall at the time.
After the show, the newly-single star asked the blonde beauty out – and the rest is history!
"They've been dating for about two months. She went on 'The Late Show' in mid-November and said Nick had reached out to her and tried to get her to lip-sync battle with him. She declined, but then he asked her out to a drink and she accepted. They've been seeing each other since," the source told Page Six.
- Billie Eilish’s Brother At War With Nick Viall After Ex-Bachelor’s Girlfriend Natalie Steals Birthday Tribute Written By Musician's Lover Claudia Sulewski
- Courteney Cox Reacts To Fans’ Claims She Looks Like Caitlyn Jenner
- Fights & Jealousy! The Truth Behind 'Bachelor' Nick Viall & Fiancée Vanessa's Split
The actress reportedly even celebrated her 40th birthday with Viall, 37, and other pals this past Saturday in Los Angeles.
As RadarOnline.com readers know, Viall and Jones are not the first Bachelor-Hollywood couple to arise in the past few months. BIP alum Wells Adams is also currently dating Modern Family star Sarah Hyland!
Are you surprised Nick Viall has already moved on, and is now dating January Jones? Sound off in the comments below.
We pay for juicy info! Do you have a story for RadarOnline.com? Email us at email@example.com, or call us at (866) ON-RADAR (667-2327) any time, day or night.