The 29-year-old actress attended the band's performance at the Barclays Center in Brooklyn, where she was joined by her parents, Dina and Michael Lohan, as well as her younger sister, Ali.
The Mean Girls star's stunning green ring, which she rocked on the all-important ring finger, shined bright alongside her sparkling, tassel-covered white jumpsuit with a plunging neckline.
Lindsay was all smiles in the pic she shared to Instagram commemorating the event, in which her sizable new ring stands out vibrantly.
Lindsay and her 22-year-old fiancé have been dating for less than a year, and the actress only confirmed their relationship in March, gushing to The Sun, "I do have a boyfriend and he is a great guy."
According to her mom, the entire family is already enamored with the Russian entrepreneur.