Credit: Kevin Mazur/WireImage

To celebrate his guest appearance on Saturday Night Live in NYC Saturday, Justin Timberlake hit up the show's weekly after party at Asellina in Gansevoort Park Hotel.

On his arm was his fiancee Jessica Biel, who, sources tell Us Weekly, was happily flaunting her engagement bling!

"Jessica was showing off her ring," the source tells Us.

Biel, 29, has yet to debut her new bling in public since Timberlake, 31, popped the question over the holidays in Jackson, Wyoming. The pair have been dating on and off for four and a half years.

"They were very lovey. Holding hands," another source tells Us of Biel and Timberlake's PDA at the soiree. "They kissed a few times in front of the crew."