Lindsay Lohan celebrated turning 23 on Thursday with a romantic lunch date with on-again, off-again girlfriend Samantha Ronson.

The volatile couple were snapped looking happy and relaxed in each other's company as they dined - and smoked - al fresco at Tra Di Noi in Malibu.

Lindsay and Sam at Tra Di Noi in Malibu

Later Lindsay carried on the party with a group of pals at Cecconi's restaurant in West Hollywood, and, later still, at Bardot night spot.

Samantha missed out on Lindsay's lavish celebrations at the MGM Grand hotel and resort in Las Vegas this past Saturday but the pair have more than made up for it since.

After dancing the night away together at Los Angeles nightclub The Ruby on Wednesday, they exchanged soppy Tweets the following day.

The DJ wished her girlfriend happy birthday followed by a kiss and hug, prompting an "Awww thanks baybee lol" from the actress.

Lindsay's birthday celebrations step up a gear later in the day

Lindsay and Sam split earlier this summer, but reunited during a visit to London in June.

See the birthday girl through the years below