One of the first times Faris and Barrett, 47, were spotted together was in September at a carnival that the Mom star took her and Pratt's 5-year-old son, Jack, to for the day.
"It was pretty casual," an eyewitness told ET. "At the time we figured they just knew each other and were hanging out together at the carnival."
"It wasn't guarded, it was friendly and a bit flirty," the eyewitness added. "She was definitely happy. She seemed carefree and very relaxed. It seemed flirty, for sure, but there wasn't any PDA or obvious signs that they were a couple."