The couple walked close together while leaving Il Cielo restaurant in Los Angeles after their secret date night.
While the birthday boy wore an embroidered jacket with a beanie and jeans, Kourtney opted for a pair of black striped sweat pants with a denim jacket, which she accented with red strappy heels.
She was photographed earlier in the day filming for Keeping Up With the Kardashians, wearing the same outfit.
After filming all day, we're told Kourtney arrived at Younes' home around 8:30 p.m. on May 5. She left her car at his place so they could drive together.
Younes drove Kourtney to Il Cielo in his Ferrari. They arrived at the restaurant around 9:30 p.m. and stayed for three hours as they celebrated his 24th birthday together.
We're told the couple spent the night "getting cozy" in a back corner of the restaurant where they were spotted holding hands and kissing.