Gwyneth Paltrow surprised “little sister” Kate Hudson on her 40th birthday.

The Hollywood actresses are long-time friends and got together on Friday morning to celebrate Hudson’s milestone.

Paltrow posted a picture to Instagram showing the two smiling while in workout clothes, revealing they had spent the morning doing yoga.

After their workout Paltrow was one of Hudson’s celebrity friends throwing a surprise, low-key event at a Los Angeles coffee shop, which was attended by stars including Hudson’s mother, Goldie Hawn and step-father Kurt Russell.

Paltrow, 46, captioned her post: “Birthday yoga and a surprise for my little sister @katehudson You radiate happiness and make everything fun.

“We all love you so much. #lordylordylookwhos40.” Hudson later marked the occasion in a similarly understated way, sharing a selfie in bed with her three children.

Along side the picture, she wrote: “My wishes came true. Thank you for all the love today. #ThisIs40.”

Hudson rose to fame after starring in Almost Famous in 2000, which won her a Golden Globe as well as an Oscar nomination for best supporting actress.

Her other films include How To Lose A Guy In 10 Days (2003), Raising Helen (2004) and You, Me And Dupree (2006).