The couple went bowling and spent time at the Vegas resort's poker room.
The pair was first spotted on Friday where they met up with friends while staying at Vegas' Red Rock Casino Resort and Spa. That night, the group enjoyed dinner at T-Bones Chophouse inside the resort, followed by drinks at the holiday-themed Merry Crimson bar.
MGK, 30, and Fox, 34, were also seen walking through the casino holding hands, as well as enjoying the resort's poker room and bowling lanes. The two appeared to be having fun and enjoying their time together and with friends all weekend, the eyewitness says.
Fox's getaway come on the heels of her ex, Brian Austin Green's, PDA-filled Hawaiian vacation with Dancing with the Stars pro Sharna Burgess. Fox filed for divorce from her ex, with whom she shares three kids with, in November.
Last month, a source told ET that Fox's romance with Kelly is "healthier" than her relationship with Green.
"Megan is the type of person who likes to keep her partners on their toes so one day she can be super hot and another, she can be cold," the source said. "MGK doesn’t mind the back and forth and they’re definitely more 'on' than 'off' on most days. Megan’s relationship with MGK is healthier than her relationship with Brian was, especially during their last year together."
In fact, Fox and Kelly are "going strong," so much so that Kelly is thinking about next steps.
"MGK and Megan make each other laugh and that’s a big thing for Megan. They keep each other smiling," the source said. "MGK totally sees marriage in his future with Megan and friends could 100% see them getting engaged within the next year."
However, the source noted, "Megan doesn’t think about getting engaged [or] married and she doesn’t put a timeline in place and it’s not something that really crosses her mind."
Whether they'll get married, the source said the couple understands "one another because of their strong connection and because they are both parents." MGK has a daughter of his own.
"They both get it and it’s easy for them to empathize with each other whether it’s related to parenthood, their careers, etc," the source said. "MGK felt like he was going down a bad path before he met Megan and she has really helped him see things in a new light.”