The beaming pair were spotted at Los Angeles airport on Friday, and certainly looked thrilled to be reunited.
Onlookers said the happy couple, dressed down in jeans and sunnies were 'smiling the entire time.'
Taking to Twitter shortly afterwards, Cory Monteith thanked fans for their ongoing support.
'Sending out big love to everyone,' the 30-year-old actor wrote. 'Thank you for the continued support! It means the world to me!'.
Lea Michele was similarly thrilled to have her Hollwood beau back. 'Today is a great day :) Love you all! Xo,' she wrote.
Cory Monteith has checked himself into rehab for substance addiction at the beginning of the month, with a spokesman confirming it was a 'voluntary' move, supported by Lea Michele.
Cory's spokesman said: 'He graciously asks for your respect and privacy as he takes the necessary steps towards recovery,' while Lea Michele said: 'I love and support Cory and will stand by him through this,' she said. 'I am grateful and proud he made this decision.'
Cory's Glee co-star also spoke out in support of his decision, telling reporters: "It takes balls to go through that privately, but to go through it publicly like that - balls.'
Meanwhile, Jane Lynch told CB!: 'We’re giving him his time. I can’t wait for him to come back and he will.'
A spokesman for 20th Century Fox TV said: 'Cory is a beloved member of the Glee family and we fully support his decision to seek treatment. Everyone at the show wishes him well and looks forward to his return.'
It's thought Cory underwent treatment at a private centre in California.
The 30-year-old actor, who first entered rehab aged 19, has been open about his battles with substance abuse in the past.
'I don't want kids to think it's okay to drop out of school and get high, and they'll be famous actors, too,' he said in an interview in 2011.
'But for those people who might give up: Get real about what you want and go after it.'
We're glad you're feeling better, Cory!
WATCH: Lea Michele and Cory Monteith cosy up on the red carpet…
Are Lea Michele and Cory Monteith Hollywood's hottest new couple? What do you think of Cory's decision to seek treatment for his addictions? Let us know in the comments box below…