Lindsay Lohan and Sam RonsonEMPICS Entertainment

Lindsay Lohan flew into Chicago over the weekend to help Samantha Ronson celebrate her 32nd birthday, fueling rumors that the two are  back together.

The on-off couple seemed to be having a ball of a time at the Crimson Lounge in Hotel Sax, and spent the weekend together.

Love certainly seems to be blooming once again between the DJ and the celebrity actress.

"They kept smiling at each other and holding hands," a source said. "It was very sweet. Not only did Lindsay make a toast to Sam, but because Lindsay was so caught up in the moment, she twittered a special message to Sam to let her know how happy she was.”

Life is certainly looking rosy for Lohan at the minute.  The latest positive news on the love front comes right after she confirmed she was cast in the new movie “Machete,” a spin-off of Robert Rodriguez’s popular film “Grindhouse.”

Lohan, a twitterholic it would seem, posted this message on her account: “Something was made official today!!!!!!!!!" along with a link to "Machete's" page, which shows she’s been cast alongside screen legend Robert De Niro , action movie hero Steven Seagal and “Superbad” funny man Jonah Hill.

Happy Days for the newly blond Lohan!