Heidi Montag, Spencer Pratt 'spotted kissing'

Heidi Montag and Spencer Pratt have been photographed kissing, suggesting that they have decided to give their marriage a second chance.

The couple were spotted by Radar Online embracing at the Santa Barbara Zoo yesterday as they celebrated Montag's 24th birthday together.

They first sparked rumours of a reunion over the weekend when they were seen attending a breast cancer fundraiser together in Los Angeles.

Pratt later suggested that the couple's recent experience in Costa Rica, where they were briefly detained at the airport on suspicion of illegal arms possession, had brought them closer together and he was hoping Montag would drop her divorce proceedings.

Montag also fuelled hope that their marriage could be back on track when she told The AP: "As far as I'm concerned the last thing in the world after everything we have just been through is to go through with this divorce. But we are just taking life second by second."

The couple - who met while filming The Hills - married in April 2008.