Hartson was part of the BT Sport team providing coverage for Leicester City’s 1-1 draw with West Ham.
The aircraft owned by Leicester owner Vichai Srivaddhanaprabha could be seen in the background of the studio taking off.
For reasons not yet known, the helicopter lost flight and crashed just outside the King Power Stadium.
Pilot Eric Swaffer bravely managed to steer the helicopter away from a busy area which contained a full TV compound, fans leaving the ground, stadium staff and police.
The helicopter was engulfed into flames after crashing and all five people that were on board tragically lost their lives, Leicester confirmed on Sunday.
Hartson revealed on Twitter on Saturday evening that despite seeing the vehicle take-off, the BT Sport staff were initially unaware it had crashed.
He tweeted: “My thoughts are with Glenn [Hoddle].. and the terribly sad news of the helicopter crash.. we were unaware sitting in the Bt sport studio of what had happened outside the stadium. We await more news.”
BT’s Premier League tonight show was cut short as the studio evacuated while emergency services attended the scene.
Jake Humphrey confirmed via Twitter that BT are taking care of their staff who were affected by Saturday’s events.
After a fan on Twitter asked the presenter if BT have offered support, he replied: “They’re being excellent to everyone involved. Thanks for checking.”
It was a difficult day for all involved at BT.
Former England manager Glenn Hoddle collapsed in their studios early on Saturday afternoon.
This saw their results show cancelled for obvious reasons.
Simon Daniels revealed his “natural instinct” of first aid training helped the former England boss Hoddle.
Daniels, a member of the production crew, gave Hoddle special medical attention after he suffered a heart attack.
On Sunday, it was confirmed Hoddle remained in “a serious condition” but was responding well to treatment.