Actress Dakota Johnson has laughed off rumours that she is pregnant with partner Chris Martin’s baby.

The 50 Shades Of Grey star was reported to be expecting with the Coldplay star after she had a party at which blue and pink balloons were released, sparking speculation it was a gender reveal event.

However, she has now explained that it was just her birthday party that happened to have balloons, that were then accidentally released into the air.

Appearing on Ellen DeGeneres’s chat show, she was told by the host: “That is a mighty tight outfit for someone who is pregnant…”

Johnson, 29, laughed before adding: “The only thing I’m pregnant with is a lot of really good ideas.

“But not any babies.”

She added: “It was my birthday and there were balloons that happened to be pink and blue, and so then I was pregnant?

“I didn’t know that the balloons were going to be released, they were just in an arch.

“But I guess that accidentally happened, one of the ends got let go. But a lot of people congratulated me.”

Johnson, who is next appearing in horror dance film Suspiria alongside Tilda Swinton and Chloe Grace Moretz, has reportedly been in a relationship with British music star Martin, 41, since last year.