Host of the ceremony Corden planted a kiss on the BBC Radio 1 DJ and sat on his lap towards the end of tonight's ceremony.
When Corden asked Grimshaw what his favourite part of the evening had been, he joked: "This is my highlight."
Grimshaw added that he was "ready" for Emeli Sandé's closing performance, to which Corden quipped: "You certainly feel ready. I just worry about standing up."
Sandé, who won 'British Female' and 'British Album' for Our Version of Events at the ceremony, went on to end the show with a performance of tracks from her record.
Other big winners on the night included Ben Howard, who took home 'British Breakthrough' and 'British Male', and Mumford & Sons, who beat One Direction to receive the 'British Group' prize.
Photo gallery - Brit Awards 2013 in pictures:
Copyright: PA Images Yui Mok/PA WireWatch Little Mix, Labrinth and Ed Sheeran chat to Digital Spy at the Brit Awards below: