Brendan Rodgers' appointed at Celtic has created great optimism around Parkhead.
Lennon was one of Rodgers’ biggest rivals in the race for the job at Parkhead, but he narrowly missed out to the former Liverpool boss.
Rodgers is now set to take charge of the Bhoys for next campaign, and Lennon believes that the 43-year-old will do an excellent job.
“I know Brendan well,” Lennon said. “I actually went to watch him coach at Reading. I saw him again when we played them in the cup at Liverpool.
"He can phone me any time, but he knows that anyway. I texted him to congratulate him on the job and if he needs anything, which he probably won't because he is experienced enough anyway, then it's not a problem."
Lennon was interviewed by the Celtic board, but they opted against re-appointing him in the end.
Lennon was in charge at Celtic between 2010 and 2014, and he delivered a good amount of success to the Glasgow giants, with many supporters of the Bhoys open to a return.
However, Rodgers’ arrival at Parkhead has also been welcomed by Celtic fans and there is great optimism for the future.
Rodgers is a high profile appointment for Celtic, and he is expected to be an upgrade on his predecessor Ronny Deila.
Rodgers’ first task at Celtic will be to ensure that they qualify for the Champions League - something that Deila did not manage to do during his time in charge.