Back then Lydiate was a key cog for Wales and was named Player of the Championship for his performances but an ankle injury ruled him out of this year's campaign.
Now back in domestic action for Newport Gwent Dragons, Lydiate will take to the Millennium Stadium pitch this weekend for the first time since helping Wales to the Grand Slam as his side face the Scarlets.
And he revealed he did not find it easy to sit and watch Wales recover from an early defeat to Ireland to win a fourth RBS 6 Nations title in nine years.
"It has been savage watching Wales since because I find it so hard not being involved. Everyone has ups and down days and I am a pretty positive person generally," he said.
"But it is when you miss out on chances that it hurts. After being part of a Grand Slam but not playing for Wales this season has been hard to take.
"I was at the England game and, while I was chuffed for the boys, I found it difficult. The atmosphere was amazing and not something I had experienced before even at the Millennium Stadium.
"But it is exciting to come back to the Millennium Stadium because it has been a long time since I have played there.
"It was over a year ago when I played against France which was not a bad occasion!"