Zebo took compassionate leave to fly home to Cork on Monday after John Geary died following a short illness at Cork University Hospital the previous day.
The Munster star was able to attend his grandfather's funeral on Tuesday before flying back to Ireland's training base in Guildford later that day.
And the 25-year-old, who toured Australia with the Lions in 2013, revealed he's been welcomed back with open arms by his team-mates.
"It's been a tough couple of days, but getting back into camp and around the lads has made things a little easier," said Zebo.
"He was like a father to me. He lived right around the corner from me. I would have seen him and my grandmother every single day and I have great memories of them and he'll be missed.
"They were very quick in coming up to me and just saying how sorry they were and how upset I must have been.
"But five minutes later they were making jokes and slagging me off. They've just been great with helping me take my mind of the tougher side of it.
"I thought it would have been a lot harder than it was, but I was able to snap into it straight away so that was a nice confidence booster."
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