Last week, Chelsea signed Germany international Havertz from Bayer Leverkusen on a five-year contract in a deal worth £71million.
Havertz became Chelsea’s second most expensive signing after Kepa Arrizabalaga and will bolster Lampard’s options in midfield.
Following Havertz’s move to Stamford Bridge, Bild claimed Mount had reacted badly to his arrival and was now concerned about his playing-time under Lampard.
But addressing the rumours, Lampard said on Thursday: ‘I saw the story about Mason Mount and I know it was an absolute fabricated from somebody, particularly if it came from the German end.
‘I’m not sure if he has any relatives out there or friends he would talk to, it’s a strange angle for that to come from Mason.
‘What I do know is the young players we’ve got in the team and the way football is at a club like Chelsea, if you’re a young player that’s got a foot in and the club brings in players around you that raise levels, or you hope raise levels, the players should, and hopefully will, raise their levels and everyone improves.
‘I will be fair when I pick the team. I don’t pick the team on whether you’ve come through the academy or not. I pick the team on how it should be picked every week on how they train and how we’ve been performing.
‘Everybody should be positive going into the season. Train and play as well as they can and worry about the unity of the squad and the results we get as a team.’
Lampard also praised Havertz’s versatility and insisted Chelsea’s new signing can play in a number of positions.
‘He’s actually very happy to come and help the team and give us different qualities in different areas. It’s not one we have to nail down.’