Kate Mara is pregnant.

The 35-year-old actress and her husband Jamie Bell attended Sir Elton John's annual AIDS Foundation Oscars Party in West Hollywood, California, on Sunday (24.02.19) and the 'Fantastic Four' actress showed off her growing bump in a short long-sleeved white and silver dress as she posed for pictures at the event.

Kate's visible pregnancy comes a month after it was first reported she had been confiding her happy news in friends at the Golden Globe awards, to which she wore a billowing dress with a cut-out centre that masked her changing shape.

According to a source at the time, the 'Pose' actress was overheard telling Emily Blunt the news, and added that she and 32-year-old Jamie ''are thrilled''.

The insider added: ''However she was nervous that people would find out before she made the announcement official as she is already showing.''

Neither Kate or Jamie - who already has a five-year-old son from his previous marriage to Evan Rachel Wood - have yet made any public comment on the news.

Meanwhile, Kate recently said she has become very ''protective'' of the ''incredible'' bond she has shared with the 'Man on a Ledge' star since getting married.

She said: ''I love knowing that I have a partner for life. I feel very proud to call Jamie my husband and to have made that commitment to him ... now that Jamie is legally a part of my family, it's such an incredible thing. I'm very protective of our marriage.''

And the 'Morgan' star revealed she and her 32-year-old spouse keep their relationship strong by sticking to a rule which means they'll never go more than two weeks without spending time together.

She added: ''All the travelling we both have to do for work can make it hard, but we have a rule that we will never go longer than two weeks without seeing each other. Even if we have to spend all day travelling to have just 24 hours together, it's worth it in order to have a strong relationship.''