Ashlee Simpson and Evan Ross are officially dating, declaring their love as girlfriend and boyfriend from New York City to California, according to JustJared.

Jessica Simpson's sister, 28, has fallend for Diana Ross' son, 24, after having a longtime friendship. Cameras caught the new couple holding hands and walking with Simpson's son, 4-year-old Bronx in Venice Beach, Calif. on Sunday, JJ reported.

The twosome hung out with some friends on the deck of a private residence and had a lot of fun. 

[For the photos, click HERE.]

Both entertainers also showed more public displays of affection during a recent trip to NYC, where they went public with their romance at Simpson's big sister's Fall 2013 campaign launch. After leaving the city, the two were hand in hand while walking through LAX Airport back home in LA on July 31. 

While romance rumors were circulating just last month before their public declaration of love, a source told US Weekly that the then-friends had become very close before falling for each other.

"Evan and Ashlee have been friends for a really long time, probably ten years," the source said. "They know each other from the club scene and have tons of mutual friends."

Another source close to Simpson said that the couple are very in-sync with each other.

"It helps that they were friends first," the insider said. "They have a long bond. They already know each other really well."

Tell us what you think of their new romance in the comments section below!