Chris Martin brings son onstage to celebrate birthday

Chris Martin surprised his son Moses by bringing him onstage during a concert so the crowd could sing him Happy Birthday.

The Coldplay frontman headed to South America last week (ends03Apr16) to start the next leg of the A Heads Full of Dreams world tour and his estranged wife Gwyneth Paltrow brought their two children Moses and Apple to visit him in Peru over the weekend (02-03Apr16).

But Moses got more than he bargained for when he stood in the wings to watch his dad at the Estadio Nacional de Lima in the Peruvian capital on Tuesday night (05Apr16).

Video footage posted on Instagram by Gwyneth, 43, shows Chris, 39, encouraging Moses to come out from the wings to screams from thousands of fans. The actress also comes onto the stage as a member of crew brings out a birthday cake, complete with burning candles.

"When your dad wishes you an early 10th birthday at work...#coldplaylima," she wrote in the caption.

Fan footage from the concert shows the crowd singing, "Cumpleanos feliz", which is Spanish for Happy Birthday, to mark Moses' upcoming 10th birthday on Friday (08Apr16).

Gwyneth has been posted images on Instagram showing her Peruvian holiday with Moses and Apple, 11. The series of snaps shows the children stroking what appears to be a llama and visiting the historical site Machu Picchu.

Gwyneth and Chris announced their separation in 2014 after more than ten years of marriage and are reportedly close to finalising their divorce. The former couple, who share joint custody of their kids, are remaining friends for the sake of their family and socialise often.

"Chris is always welcome at my house and I at his. We go on holidays together - it's all very relaxed," she recently told You magazine.

The A Heads Full of Dreams tour ends in September (16) in California.