The British actor is said to have turned to the fake nicotine device to shake his nasty habit after 37-year-old 'Inception' star Leonardo recommended them to him, according to The Sun newspaper.
Robert became good pals with Leonardo after being introduced by their mutual friend Reese Witherspoon and insiders previously said he views him as a "role model".
The 26-year-old actor was spotted puffing away on the electronic stick at a party to celebrate the Los Angeles premier of Kristen's movie 'On The Road' on Saturday night (03.11.12) in the Roosevelt Hotel.
The couple - who recently reconciled following her "momentary indiscretion" - did not attend the screening together but Robert showed up to support his 22-year-old girlfriend at the after party and spent the evening on the Garden Terrace with her.
Sources told EOnline.com that the 'Twilight Saga' co-stars were spotted chatting with actress Amy Adams and seemed in good spirits although they weren't affectionate.