Jennifer Garner 'hated' McConaughey's Dallas Buyers Club weight loss

Actress worried for health of co-stars.

Jennifer Garner has revealed how she 'hated' the transformational weight loss of her 'Dallas Buyers Club' co-stars Matthew McConaughey and Jared Leto.

The actress stars as a doctor in the movie, and had to watch while 43-year-old McConaughey lost 50 pounds, dropping from 185 pounds to just 135.

“I hated it,” she told our cohorts at Yahoo! Movies in the US.

Emaciated... Garner 'hated' McConaughey's weight loss (Copyright:

“I hated seeing Matthew so - I mean, he looked ill. He looked legitimately really, very ill. It was all I could do to not cry... because he really looked that sick.”

In the 80s-set film, based on a true story, McConaughey plays Ron Woodruff, a Texas man who is diagnosed with AIDS and with Jared Leto's transsexual fellow sufferer Rayon starts a prescription drug smuggling business.

Though Leto lost less weight, at 30 pounds, his transformation was more acute than McConaughey's.

Emaciated... Leto in pics released last year (Copyright: Terry Richardson)

“It was awful to watch,” Garner added.

“He would look totally out of it, like he could fall over, until they said action and then he would snap to and focus and be able to do anything. But he was scary.”

Both actors are reportedly gaining 'Oscar buzz' for their performances in the movie.

It's due out in the UK on February 7.