OK, I have never heard of this celebrity (perhaps due to the absence of a TV in my house) BUT it appears there were claims of her being a Muslim. LM have cleared this one up by linking to a tweet. Jameela Jamil confirms she is not a Muslim:
@afra_chaudhary no i don't mind you asking at all! I'm not a muslim. Just wasn't brought up with any religion at all...xxx
However, there are mitigating circumstances for the claim that this lady is a Muslim as she is of Bangladeshi origin (as well as her name) BUT it is not true. She is not a Muslim.
Christian Missionary Pastor converts to Islam
Bible: Muslims are blessed