LOS ANGELES, Aug. 25 (UPI) -- Justin Bieber helped ring in Sofia Richie's 18th birthday Wednesday.
The 22-year-old singer celebrated with the model at the Doheny Room in Los Angeles and was spotted leaving the venue with Richie that evening.
"Justin was there but they were not acting overly PDA," a source told E! News of the rumored couple. "[They had] some touching gestures, [but kept it] low key."
Richie and her friends stopped by The Nice Guy restaurant prior to meeting Bieber at Doheny. She and her pals had also celebrated at 1OAK club the night before.
"Many friends came out for Sofia's birthday," the insider told E!. "A lot of dancing and celebration went down. She was fully taken care of with whatever she wanted."
Richie, the daughter of Lionel Richie and sister to Nicole Richie, was first linked to Bieber this month. Sources previously told Us Weekly the pair are "casually" seeing each other but denied the romance is anything "more" for now.