Forest boss Aitor Karanka snapped up the 32-year-old attacker on a free transfer last month what is his third stint at the club, having paid around £3.5 million to bring him to Middlesbrough in January 2017.
The Algeria international, who has 40 caps for his country, has only played two games for the Reds so far - both defeats - but Tomlin believes that Nottingham Forest can only be a better side with someone of that calibre.
“I have had a few battles with Adlene over the years and he has come out on top a few times – and so have I,” he said to The Nottingham Post.
“He is such a good player, he is a battler and a nice guy.”
Karanka, who only took the Forest job in January after Mark Warburton was sacked, will already be looking at next season.
Forest aren't safe from relegation, but a seven-point cushion from the bottom three means that dropping down into League One isn't an imminent threat, though a 17-point gap from the top six means that the Spaniard's troops haven't got much left to play for.
That being said, it should, in theory, be an exciting summer at the City Ground as the former Real Madrid assistant looks to build a squad capable of winning Premier League promotion, having done so with Boro in 2016.
And the addition of Guedioura is certainly a very good start.