Felipe Massa could not say no to another year in Formula One and is relishing the chance to help Williams be competitive in 2017.
The Brazilian bid an emotional farewell to F1 in Brazil and Abu Dhabi in the final races of last season, the 35-year-old stepping aside for youngster Lance Stroll.
However, Valtteri Bottas' move to Mercedes to replace the retired Nico Rosberg left a gap in the Williams line-up and the experienced Massa was the man the team turned to.
Massa admitted he was surprised to be approached, but had no hesitation in accepting their proposal, the former Ferrari driver signing a one-year deal.
"I'm back, here I am again, it is a good feeling to get back to the team and meet everybody again," he told Sky Sports News.
"I had a phone call in December, it was just after the Christmas party, Claire [Williams] calls me and I was thinking she was going to say 'nice to have you here, thank you for everything' but then she said 'are you ready to carry on and race for us next year? We really need you'.
"After we had this conversation it was very difficult for me to say no to keep working for a team that I really love to be part of.
"Especially in a year when everything starts from zero. Completely different rules for the cars, it will be a very difficult year from the physical point of view for the drivers - and I like that.
"I like new things starting so I'm sure my experience can help the team. I hope to have a competitive car and to grow a lot from the first to the last race. I'm really motivated.
"Definitely it was a little bit strange for me, I had amazing feelings in last two races, everything was perfect, so it was difficult to go back but it's what I love to do. I am ready, motivated, training hard and hope have competitive season."