The model-and-actress plays Shia LaBeouf`s on-screen girlfriend in the Michael Bay-directed film but was stunned to be given the job. She said: "I went to the casting unaware they were looking for a new female lead. We were told it was for a `nemesis` role and I left thinking I was awful. The next day I was offered the lead! "I met with Shia that evening and within three weeks I was on set shooting my first scenes..." Rosie - who shot to fame as a Victoria`s Secret model - won`t give too much away about her alter-ego Carly, apart from her nationality and job. She said: "She`s English and is working for the British embassy ... I can`t tell you more! That`s all I can say for now!" Shia - who plays Sam Witwicky in the films - has previously promised the third `Transformers` movie will be more concise and with a clearer direction, after confessing that he hated the 2009 instalment. He said: "There are a lot of people that liked the second one, but I hated it. I just didn`t enjoy it. "I thought we missed the mark. I got confused, I couldn`t see what the f**k was going on, you know, with certain robots ... I couldn`t decipher what was happening. "I know that directors Michael Bay and Steven Spielberg are dedicated to making the best movie we possibly can, and we`re not going to miss next time." `Transformers: Dark of the Moon` is released in the summer.