One of Lindsay Lohan's birthday gifts included a token of commitment from close friend Samantha Ronson.

OK! magazine reports that the pair have confirmed their romance and that the jewellery was not an engagement ring but simply one of the actress' birthday gifts.

"Sam took Lindsay shopping to celebrate her 22nd birthday," a friend of the pair revealed.

The ring is said to be a Cartier diamond worth £11,000 and Lindsay is apparently "thrilled" with the gesture.

Lindsay, who turned 22 on July 2nd, has made her party ideas last an entire week, according to reports. She held a prom-themed birthday bash at Teddy's nightclub in the Hollywood Roosevelt hotel and then went to Disneyland with DJ Samantha a few days later.

Samantha, who DJ'd at the prom party, is the sister of Mark Ronson, famous for working alongside Amy Winehouse, Lily Allen and Robbie Williams.

Lindsay recently told KIIS FM's Ryan Seacrest that she wants this year to be happy and healthy and hopes she remains with the person she cares about, reports Usmagazine.com.