Pregnant actress Keira Knightley has missed a number of key engagements during the Hollywood awards season because she is battling ill health.

The Atonement star, who recently confirmed she is expecting her first child with husband James Righton, had been due to hit the campaign trail in support of her acclaimed new movie The Imitation Game, but she has been too sick to attend events, according to the film's director Morten Tyldum.

He tells New York Post gossip column Page Six, "Keira's been not feeling well last week. So she's been home."

When asked whether Knightley is suffering from morning sickness, he replied, "I don't know."

It is not yet known whether Knightley will be well enough to attend the Golden Globe awards in Los Angeles on Sunday (11Jan15). The Imitation Game is nominated for five prizes, including the coveted Best Motion Picture, Drama title.