The "Spider-Man" star and Lohan recently appeared together in a promo video for the track 'Blue', taken from the final album by rock band REM.
Lohan and the 34-year-old actor met while shooting the video, which was filmed in February 2011 and directed by Franco himself, reported Digital Spy online.
Franco said that he and the "Liz & Dick" actress were once very close friends, but have since drifted apart.
"Lindsay and I had reconnected at that time. I had been writing some poems about the Chateau Marmont (hotel in Los Angeles), and one or two of the poems involved Lindsay... I've known Lindsay for a while.
"It was at a moment where it seemed like she was doing okay. We'd have conversations on the phone, and she seemed like she was doing okay. I haven't talked to her in a long time because it seemed like she was getting into some more trouble. I've tried to help her," Franco said.
The 26-year-old actress has recently run into legal troubles, with a series of arrests and charges stemming from alleged assault and reckless driving.
"I think one of the reasons it's so hard is when she gets in trouble, she gets all this attention and I'm sure she gets book offers. Like, she goes to jail, and instead of feeling like, 'I really hit a low place', she'll get a crazy offer for her jail memoir," Franco added.