Cameron and Justin's Engagement Party

Cameron Diaz and Justin Timberlake threw a lavish party last weekend to celebrate their engagement.

The stunning actress and the pop heartthrob, who got engaged over Christmas, hired a C$12,000-a-night penthouse at Las Vegas' Hard Rock Hotel for the bash.

While speculation was rife the smitten pair were set to wed at the party, after giving friends their invites at the last minute, they revealed they had put on the bash to simply celebrate their love.

Despite reports of a rift between Cameron and Justin's mother, Lynn, she was there to join in the celebrations.

Earlier this month, it was claimed Lynn had talked her son out of proposing to Cameron a year ago - because she didn't think he was ready to settle down.

The singer, who eventually popped the question to the stunning actress over the festive period, had wanted to propose 12 months ago and had even bought a ring.

However, mom Lynn was said to be concerned with Justin's plans and told him not to, according to America's Us Weekly magazine

A source said: "Cameron was thrilled by the ring, even though there was no proposal with it. But she has worried from the beginning that Lynn didn't like her."