AWKWARD MOMENT: J.Lo Introduces Diddy To Her Cougar Cub, Casper Smart, At The Golden Globes After Party

Looking Smart ... J.Lo looks on as Diddy and Casper shake hands

Diddy thrusts out his hand as he's introduced to ex-girlfriend Jennifer Lopez' new man Casper Smart at a Golden Globe Awards after-party.

It's never fun bumping into an ex - and when they're an A-lister, the encounter must be even more awkward.

But full marks to the rap superstar for behaving with grace towards the 43-year-old J.Lo's dancer beau - when the trio ran into each other last night [Jan. 14].

Dancing duo ... couple pose on the red carpet earlier in the night

Diddy, 43, famously dated J.Lo from 1999 to 2001 - between her ill-fated marriages to Ojani Noa and Cris Judd.

Their relationship ended in dramatic fashion, after shots were fired in a New York nightclub where he was partying with Lopez. The rapper was charged with four weapons-related offences, but later found not guilty.

The trauma of the trial spelled the end of the pair's romance - but there's clearly no hard feelings between the former flames.

They were even linked with a reunion after Lopez ended her most recent marriage, to Latin superstar Marc Anthony - and before she met toy boy Casper, 28.

Former flames ... J.Lo and Diddy during their romance