Lindsays 22nd Birthday: Ronson by her side

Lindsay Lohan turned 22 Wednesday night with an intimate prom-themed birthday bash – and a sweet smooch from Samantha Ronson.

"I just want to live a happy, healthy year and continue on the path I've been on and be with the person I care about and my family," she said on Ryan Seacrest's KIIS-FM show Thursday, declining to mention Samantha Ronson's name.

The actress – wearing a bright pink strapless micro-minidress by Bradley Bayou and an elaborate diamond necklace – arrived at Teddy's lounge inside the Hollywood Roosevelt Hotel just after 10 p.m. And her companion Ronson took the prom-theme seriously, dressed to the nines in black pants, a tuxedo shirt, bow tie and top hat with red trim.

Ronson was among the 100 attendees at Lohan's birthday bash never far behind, often keeping her hand on the small of Lohan's back.(along with Benji and Joel Madden) Other guests where former Sopranos star Jamie Lynn Sigler and Lohan's younger brother Michael – whom, the Birthday Girl greeted energetically with smiles, hugs and kisses.

Just after midnight, Teddy's wheeled out a large pink sheet cake featuring a picture of Marilyn Monroe in her iconic wind-blown white dress. The entire lounge sang "Happy Birthday" and Lohan obligingly blew out the candles. Her friends then chanted "speech, speech, speech," but the guest of honor replied jokingly, "Shut the f--- up." (Her mother, Dina, stepped in to say, "Thank you all for coming.")

Soon after that, Ronson took over the D.J. duties (replacing DJ AM), as she spun a mix of '80s tunes and current hits. Lohan – who stuck to Red Bull all evening – made several visits to the booth and pumped her fists in the air to Journey's "Don't Stop Believin'."

As the party wound down, the couple appeared to relax, even sneaking in a small peck on the lips at the DJ booth. By 1:15 a.m., the music was muted and Lohan turned out the lights with Ronson by her side.

"I've never seen her happier," a source close to the actress tells Usmagazine.com. "Everyone got along."