Unlike most people who celebrate their 21st birthday by partying and legally getting drunk, Lindsay Lohan, currently in rehab, spent her coming of age with close friends and family, including her mom, Dina, sister Ali and brother Dakota, at a beach house party in Malibu on Monday, away from Las Vegas where her initial birthday bash was supposed to take place.

According to People magazine, she continued the celebration in the afternoon by dining with a few mates to Katsuya in Brentwood, California.

"They sat down for some sushi and were just really enjoying themselves. She wasn't really noticed at all and was just happy, in a good mood," a source was quoted by People as saying.

In May, when Lindsay checked herself in Promises rehab clinic after she crashed her Mercedes into a Beverly Hills tree, her party at Los Vegas' Pure nightclub was canceled immediately.

Kate Turner, a spokesperson for Pure, said at that time: "Due to the unique circumstances, as Lindsay's birthday party at PURE Nightclub has been cancelled. We think the world of her and look forward to working with her in the future."

"We support Lindsay and wish her the best as she is taking care of personal matters at this time," she added.