Perry spends weekend with beau Orlando and his son Flynn at children's birthday party

Their romance appears to have been going from strength to strength.

And it seems Orlando Bloom is keen on Katy Perry becoming a pretty permanent fixture in his life, as she has now met his five-year-old son Flynn.

According to People magazine, the couple attended a children's birthday party over the weekend.

Katy, 31, and Orlando, 39, have been seen hanging out a number of times together in the last month.

But for the actor to invite her along to the function with his son demonstrates he sees the singer as being in a relationship with him for the long haul.

The pair attended the birthday party at Robert Downey Jr's home.

Katy was seen in the car sipping coffee while Orlando was behind the wheel.

The Teenage Dream singer had her hair pulled back in a ponytail as she sported natural, complimentary make-up on her face while Orlando sported circular retro shades and had his locks elegantly dishevelled.

The source said the couple spent 'all day together' on Saturday.

According to the insider: "Katy even sat in the back of the car with Flynn when Orlando drove them to the party."

The couple were both first seen together at the Weinstein Co. and Netflix Golden Globes afterparty in January.