Lindsay Lohan's pal fears for wellbeing

Lindsay Lohan's pop star pal Tom Parker expressed his concern for the actress' wellbeing after seeing pictures of her stumbling out of a London hotspot.

The Mean Girls actress headed to rehab last year (13) to receive treatment for substance abuse following years of personal troubles and legal woes, and she has since vowed to maintain a sober lifestyle.

Lohan moved to London to kickstart her acting career by starring in a West End production of Speed-the-Plow in August (14) and one of her pals from The Wanted, who she befriended during their tour in 2012, grew concerned after seeing pictures of her leaving celebrity haunt The Chiltern Firehouse looking worse for wear.

Parker tells British newspaper The Sun, "I chatted to her a couple of days ago because I saw a photo of her in the newspaper staggering out of a nightclub... I wanted to check she was OK, so I asked her what she was doing.

"She told me she had simply fallen over and I was like, 'Really?'... She's had a rough time but she's a sweet girl and a great actress... none of us want to see her go back to that dark place."

The actress was linked to Parker's former bandmate Max George. The group went on an indefinite hiatus earlier this year (14).

Lohan's run in Speed-the-Plow ends in November (14).