Punk icon Patti Smith once tipped on/off lovers Kristen Stewart and Robert Pattinson to play herself and tragic photographer Robert Mapplethorpe in the film adaptation of her acclaimed memoir Just Kids.

The Because The Night rocker is currently adapting the 2010 autobiography for the big screen and she admits she initially thought the Twilight couple would be the perfect casting.

She tells Entertainment Weekly magazine, "I remember the very first time I saw Kristen Stewart and Rob Pattinson together, when they were younger, and I thought, 'Those two kids could have easily played us when they were first starting.'

"There's something in his eyes. And Robert was also a bit shy, and a bit stoic. Kristen has a very special quality. She's not conventionally beautiful, but very charismatic."

But Smith insists she's gone off the idea of pushing for the casting of the newly-reunited real-life couple - because they're too famous.

She explains, "Robert and I were very young. We were 20. We were unknowns, and I think it should be unknowns in the film."