Megan Stammer's stepfather said he "can't wait to be reunited with Megan" after the missing teenager was found in France earlier on Friday.
Megan has spoken to her parents, while Forrest has been arrested on child abduction charges in Bordeaux and extradition procedures are underway. Channel 4 News reported that Megan will be flown out of Bordeaux airport back to the UK this evening.
The programme added that Forrest will appear before a French court tonight as well as on Tuesday. BBC News said that Forrest was being questioned by French police and was free to return to the UK if he chose - in which case he would be escorted on to a plane in Bordeaux.
Otherwise police will look at whether or not to charge him on Tuesday, the channel added.
It also said that Megan's mother was due to arrive in Bordeaux very shortly to collect her daughter.
Mr Stammers said at a press conference: "Danielle and I are so relieved and we can't wait to be reunited with Megan. I want to say a huge, huge thank you to Sussex Police for the work they have done, behind the scenes and the support they have given to us as a family 24 hours a day.
Martin Stammers thanked police at a press conference on Friday night
He added: "our family are overjoyed at the outcome. As you can imagine it's been an absolute emotional rollercoaster."
Paying tribute to the media and users of social networks to help them spread the word, he now requested privacy for his family, and said Twitter accounts and the Megan Missing website would be taken down temporarily.
Earlier he said he was "thrilled to bits, just over the moon" at news of her return.
Describing the "pure elation, pure relief that she is just safe and well", he told Sky News: "The relief, the outpouring of love from everyone, has just been amazing. We're so happy. As time goes on, you despair even more, but knowing Megan, knowing the girl she is, I always had that belief that she was strong enough within herself to remain safe and well."
Martin Stammers gives reporters a 'thumbs up' after the news broke
Missing teenager Megan Stammers and her Maths teacher Jeremy Forrest were spotted three times in the southwest French city of Bordeaux by members of the public, before French police arrested the 30-year-old on Friday lunchtime.
Sussex police said at a press conference that coverage in the French media had led to two suspected sightings of the couple in Bordeaux on Thursday and another on Friday, after which police confirmed that the pair were in the town.
The operation to arrest Forrest and hand Megan to child protection officers was led by French police, assisted by Sussex Police and the French office of the Serious Organised Crime Agency.
Megan Stammers has been found safe and well in France
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Forrest's parents - Jim and Julie Forrest - said in a statement: "We are pleased that Megan and Jeremy have been found safe and well. This has been an ordeal for all the families concerned.
"We would like to thank Sussex and the French police as well as the British media for their assistance.
"We are relieved that the search is finally over and everyone can now focus on a safe and secure return for them both."
Martin Stammers, Megan's stepfather, posted this picture on his Twitter account
The alarm was raised when Megan, from Eastbourne, East Sussex, failed to go to school a week ago and it was discovered that she had travelled with Forrest on a ferry from Dover to Calais the previous evening.
They had tickets to return to the UK on Sunday, but did not use them.
Megan Stammers has been found safe and well in France
Members of the family and friends also tweeted their relief.
Terry Boatwright, headteacher of Bishop Bell C of E School, which Megan attends, said: "Everyone in the Bishop Bell School community is delighted that Megan has been found and can now be reunited with her family, who must be so relieved.
"Throughout the last week, finding Megan has been everyone's priority and a major focus of our thoughts and prayers in school.
"Clearly, much needs to be done now to support Megan, and her family, as they seek to return to some sort of normality and we will do all we can to play our part in that."
Agnes Auboin, vice-prosecutor in Bordeaux, said: "The couple were found in Bordeaux by police acting on a European arrest warrant.
"They were intercepted at 1.15pm local time.
"As the girl is a minor, the maximum will be done to return her to her family. She is in good health."
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