A representative for Dakota Johnson has refuted reports that she is expecting a baby with Chris Martin.

Pregnancy rumours swirled when TMZ published photos and video from a party at the Coldplay frontman's house which showed pink and blue balloons floating in the sky above the home.

It was speculated that the actress and musician were throwing a "gender reveal party", however Johnson's spokesperson has said it was actually just a birthday party.

Johnson turned 29 on October 4.

The celebrity guests included Johnson's parents Melanie Griffith and Don Johnson, as well as some Hollywood A-listers such as Sean Penn and Julia Roberts.

The Fifty Shades of Grey star and singer-songwriter first sparked dating rumours after being spotted on a date in October 2017.

In an new interview with Tatler magazine, Johnson refused to speak about her relationship, saying: "I’m not going to talk about it, but I am very happy,"

Martin was previously married to actress Gwyneth Paltrow for 10 years before "consciously uncoupling" in 2014. They share 14-year-old daughter Apple and 12-year-old son Moses. 

Paltrow recently married writer and producer Brad Falchuk.