Ainsley was seen with a baby bump at the "The Dark Knight Rises" premiere, reported Daily Mail.
The 30-year-old model has been dating 43-year-old Guy since April, 2010 and they have a son named Rafael.
This would be "Sherlock Holmes" filmmaker's fourth child, who shares a biological son, Rocco, 11, and an adopted son, David, six, with his ex-wife Madonna.
Guy and the pop diva split in 2008 after eight years of marriage.